From d90b0f72cd65d5875eb9e4012990699cfe886c5c Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Sun, 21 Jan 2024 18:57:57 +0100
Subject: [PATCH 01/16] further updates

---
 benchmarks/WolfSheep/__init__.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/benchmarks/WolfSheep/__init__.py b/benchmarks/WolfSheep/__init__.py
index e69de29bb2d..18b86ab19ba 100644
--- a/benchmarks/WolfSheep/__init__.py
+++ b/benchmarks/WolfSheep/__init__.py
@@ -0,0 +1,14 @@
+from wolf_sheep import WolfSheep
+
+if __name__ == "__main__":
+    # for profiling this benchmark model
+    import time
+
+    # model = WolfSheep(15, 25, 25, 60, 40, 0.2, 0.1, 20)
+    model = WolfSheep(15, 100, 100, 1000, 500, 0.4, 0.2, 20)
+
+    start_time = time.perf_counter()
+    for _ in range(100):
+        model.step()
+
+    print(time.perf_counter() - start_time)

From 95864900d9e7981c8ea7240e34672f3fe792d681 Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Sun, 21 Jan 2024 19:13:00 +0100
Subject: [PATCH 02/16] Update benchmarks/WolfSheep/__init__.py

---
 benchmarks/WolfSheep/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/benchmarks/WolfSheep/__init__.py b/benchmarks/WolfSheep/__init__.py
index 18b86ab19ba..98b1e9fdfed 100644
--- a/benchmarks/WolfSheep/__init__.py
+++ b/benchmarks/WolfSheep/__init__.py
@@ -1,4 +1,4 @@
-from wolf_sheep import WolfSheep
+from .wolf_sheep import WolfSheep
 
 if __name__ == "__main__":
     # for profiling this benchmark model

From 2759244eb350ce8e38b31b08cbea46e40998893a Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Tue, 27 Aug 2024 14:01:46 +0200
Subject: [PATCH 03/16] Update __init__.py

---
 benchmarks/WolfSheep/__init__.py | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/benchmarks/WolfSheep/__init__.py b/benchmarks/WolfSheep/__init__.py
index 98b1e9fdfed..e69de29bb2d 100644
--- a/benchmarks/WolfSheep/__init__.py
+++ b/benchmarks/WolfSheep/__init__.py
@@ -1,14 +0,0 @@
-from .wolf_sheep import WolfSheep
-
-if __name__ == "__main__":
-    # for profiling this benchmark model
-    import time
-
-    # model = WolfSheep(15, 25, 25, 60, 40, 0.2, 0.1, 20)
-    model = WolfSheep(15, 100, 100, 1000, 500, 0.4, 0.2, 20)
-
-    start_time = time.perf_counter()
-    for _ in range(100):
-        model.step()
-
-    print(time.perf_counter() - start_time)

From 2f1cd4d0fa72d7edc3cb259d5249f49875706061 Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Wed, 4 Sep 2024 15:11:21 +0200
Subject: [PATCH 04/16] add a default value to agentset.get

supersedes #2067
---
 mesa/agent.py       | 43 +++++++++++++++++++++++++++++--------------
 tests/test_agent.py | 12 ++++++++++++
 2 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 225e89cda79..d952d1b0eca 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -142,12 +142,12 @@ def __contains__(self, agent: Agent) -> bool:
         return agent in self._agents
 
     def select(
-        self,
-        filter_func: Callable[[Agent], bool] | None = None,
-        at_most: int | float = float("inf"),
-        inplace: bool = False,
-        agent_type: type[Agent] | None = None,
-        n: int | None = None,
+            self,
+            filter_func: Callable[[Agent], bool] | None = None,
+            at_most: int | float = float("inf"),
+            inplace: bool = False,
+            agent_type: type[Agent] | None = None,
+            n: int | None = None,
     ) -> AgentSet:
         """
         Select a subset of agents from the AgentSet based on a filter function and/or quantity limit.
@@ -190,7 +190,7 @@ def agent_generator(filter_func, agent_type, at_most):
                 if count >= at_most:
                     break
                 if (not filter_func or filter_func(agent)) and (
-                    not agent_type or isinstance(agent, agent_type)
+                        not agent_type or isinstance(agent, agent_type)
                 ):
                     yield agent
                     count += 1
@@ -225,10 +225,10 @@ def shuffle(self, inplace: bool = False) -> AgentSet:
             )
 
     def sort(
-        self,
-        key: Callable[[Agent], Any] | str,
-        ascending: bool = False,
-        inplace: bool = False,
+            self,
+            key: Callable[[Agent], Any] | str,
+            ascending: bool = False,
+            inplace: bool = False,
     ) -> AgentSet:
         """
         Sort the agents in the AgentSet based on a specified attribute or custom function.
@@ -348,12 +348,16 @@ def agg(self, attribute: str, func: Callable) -> Any:
         values = self.get(attribute)
         return func(values)
 
-    def get(self, attr_names: str | list[str]) -> list[Any]:
+    def get(self, *args) -> list[Any]:
         """
         Retrieve the specified attribute(s) from each agent in the AgentSet.
 
         Args:
             attr_names (str | list[str]): The name(s) of the attribute(s) to retrieve from each agent.
+            default (Any): The default value of the attribute(s) to retrieve from each agent if
+                                 the agent does not have the attribute.
+                                 If no default value is passed, an AttributeError is raised if
+                                 an agent does not have the attribute.
 
         Returns:
             list[Any]: A list with the attribute value for each agent in the set if attr_names is a str
@@ -363,12 +367,23 @@ def get(self, attr_names: str | list[str]) -> list[Any]:
             AttributeError if an agent does not have the specified attribute(s)
 
         """
+        attr_names, *args = args
+
+        def get_attr(*args):
+            obj, attr_name, *args = args
+            try:
+                return getattr(obj, attr_name)
+            except AttributeError as e:
+                if len(args) > 0:
+                    return args[0]
+                else:
+                    raise e
 
         if isinstance(attr_names, str):
-            return [getattr(agent, attr_names) for agent in self._agents]
+            return [get_attr(agent, attr_names, *args) for agent in self._agents]
         else:
             return [
-                [getattr(agent, attr_name) for attr_name in attr_names]
+                [get_attr(agent, attr_name, *args) for attr_name in attr_names]
                 for agent in self._agents
             ]
 
diff --git a/tests/test_agent.py b/tests/test_agent.py
index e78a4dcec93..559ecc150a3 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -276,6 +276,18 @@ def remove_function(agent):
     assert len(agentset) == 0
 
 
+def test_agentset_get():
+    model = Model()
+    agents = [TestAgent(i, model) for i in range(10)]
+
+    agentset = model.agents
+
+    with pytest.raises(AttributeError):
+        agentset.get("unknown_attribute")
+
+    results = agentset.get("unknown_attribute", True)
+    assert all(results) is True
+
 def test_agentset_agg():
     model = Model()
     agents = [TestAgent(model) for i in range(10)]

From d168eb6f9336a736d34446c75e1c405977d97b9b Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Wed, 4 Sep 2024 13:13:20 +0000
Subject: [PATCH 05/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 mesa/agent.py       | 22 +++++++++++-----------
 tests/test_agent.py |  1 +
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index d952d1b0eca..4328c7a4b9a 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -142,12 +142,12 @@ def __contains__(self, agent: Agent) -> bool:
         return agent in self._agents
 
     def select(
-            self,
-            filter_func: Callable[[Agent], bool] | None = None,
-            at_most: int | float = float("inf"),
-            inplace: bool = False,
-            agent_type: type[Agent] | None = None,
-            n: int | None = None,
+        self,
+        filter_func: Callable[[Agent], bool] | None = None,
+        at_most: int | float = float("inf"),
+        inplace: bool = False,
+        agent_type: type[Agent] | None = None,
+        n: int | None = None,
     ) -> AgentSet:
         """
         Select a subset of agents from the AgentSet based on a filter function and/or quantity limit.
@@ -190,7 +190,7 @@ def agent_generator(filter_func, agent_type, at_most):
                 if count >= at_most:
                     break
                 if (not filter_func or filter_func(agent)) and (
-                        not agent_type or isinstance(agent, agent_type)
+                    not agent_type or isinstance(agent, agent_type)
                 ):
                     yield agent
                     count += 1
@@ -225,10 +225,10 @@ def shuffle(self, inplace: bool = False) -> AgentSet:
             )
 
     def sort(
-            self,
-            key: Callable[[Agent], Any] | str,
-            ascending: bool = False,
-            inplace: bool = False,
+        self,
+        key: Callable[[Agent], Any] | str,
+        ascending: bool = False,
+        inplace: bool = False,
     ) -> AgentSet:
         """
         Sort the agents in the AgentSet based on a specified attribute or custom function.
diff --git a/tests/test_agent.py b/tests/test_agent.py
index 559ecc150a3..0c05b78e4fc 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -288,6 +288,7 @@ def test_agentset_get():
     results = agentset.get("unknown_attribute", True)
     assert all(results) is True
 
+
 def test_agentset_agg():
     model = Model()
     agents = [TestAgent(model) for i in range(10)]

From 2a84336ba3279b36ea25693a9ad61263c8d75a7a Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Thu, 5 Sep 2024 14:03:42 +0200
Subject: [PATCH 06/16] make arguments explicit and add skip option

---
 mesa/agent.py       | 80 +++++++++++++++++++++++++++++++--------------
 tests/test_agent.py | 22 +++++++++++--
 2 files changed, 75 insertions(+), 27 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 4328c7a4b9a..375baeaceba 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -348,44 +348,74 @@ def agg(self, attribute: str, func: Callable) -> Any:
         values = self.get(attribute)
         return func(values)
 
-    def get(self, *args) -> list[Any]:
+    def get(self, attr_names: str | list[str], handle_missing: str = "error", default_value: Any = None) -> list[Any] | list[list[Any]]:
         """
         Retrieve the specified attribute(s) from each agent in the AgentSet.
 
         Args:
             attr_names (str | list[str]): The name(s) of the attribute(s) to retrieve from each agent.
-            default (Any): The default value of the attribute(s) to retrieve from each agent if
-                                 the agent does not have the attribute.
-                                 If no default value is passed, an AttributeError is raised if
-                                 an agent does not have the attribute.
+            handle_missing (str, optional): How to handle missing attributes. Can be
+
+                                            -'error' (default), raises an AttributeError if attribute is missing.
+                                            -'skip' which skips the agents missing the attribute.
+                                            'default' to return the specified `default_value`.
+
+            default_value (Any, optional): Used in conjunction with ``handle_missing='default``
+                                     The default value to return if 'handle_missing' is set to 'default'
+                                     and the agent does not have the attribute.
 
         Returns:
-            list[Any]: A list with the attribute value for each agent in the set if attr_names is a str
-            list[list[Any]]: A list with a list of attribute values for each agent in the set if attr_names is a list of str
+            list[Any]: A list of attribute values for each agent if attr_names is a str.
+            list[list[Any]]: A list of lists of attribute values for each agent if attr_names is a list of str.
 
         Raises:
-            AttributeError if an agent does not have the specified attribute(s)
-
+            AttributeError: If 'handle_missing' is 'error' and the agent does not have the specified attribute(s).
         """
-        attr_names, *args = args
 
-        def get_attr(*args):
-            obj, attr_name, *args = args
-            try:
-                return getattr(obj, attr_name)
-            except AttributeError as e:
-                if len(args) > 0:
-                    return args[0]
+        # Check if the attr_names is a single string or a list of attributes.
+        is_single_attr = isinstance(attr_names, str)
+
+        # Branch earlier based on the `handle_missing` option to avoid repeated checks
+        match handle_missing:
+            case "error":
+                if is_single_attr:
+                    return [self._get_or_raise(agent, attr_names) for agent in self._agents]
                 else:
-                    raise e
+                    return [[self._get_or_raise(agent, attr) for attr in attr_names] for agent in self._agents]
 
-        if isinstance(attr_names, str):
-            return [get_attr(agent, attr_names, *args) for agent in self._agents]
-        else:
-            return [
-                [get_attr(agent, attr_name, *args) for attr_name in attr_names]
-                for agent in self._agents
-            ]
+            case "default":
+                if is_single_attr:
+                    return [self._get_with_default(agent, attr_names, default_value) for agent in self._agents]
+                else:
+                    return [[self._get_with_default(agent, attr, default_value) for attr in attr_names] for agent in self._agents]
+
+            case "skip":
+                if is_single_attr:
+                    return [val for agent in self._agents if (val := self._get_skip(agent, attr_names)) is not None]
+                else:
+                    return [
+                        [val for attr in attr_names if (val := self._get_skip(agent, attr)) is not None]
+                        for agent in self._agents
+                    ]
+
+            case _:
+                raise ValueError(f"Unknown handle_missing option: {handle_missing}, "
+                                 "should be one of 'error', 'skip', or 'default'")
+
+    # Helper method to get an attribute or raise an error if it's missing
+    def _get_or_raise(self, agent: Any, attr_name: str) -> Any:
+        return getattr(agent, attr_name)
+
+    # Helper method to get an attribute with a default value if missing
+    def _get_with_default(self, agent: Any, attr_name: str, default: Any) -> Any:
+        return getattr(agent, attr_name, default)
+
+    # Helper method to skip missing attributes by returning None
+    def _get_skip(self, agent: Any, attr_name: str) -> Any:
+        try:
+            return getattr(agent, attr_name)
+        except AttributeError:
+            return None
 
     def set(self, attr_name: str, value: Any) -> AgentSet:
         """
diff --git a/tests/test_agent.py b/tests/test_agent.py
index 0c05b78e4fc..e201f846b49 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -278,16 +278,34 @@ def remove_function(agent):
 
 def test_agentset_get():
     model = Model()
-    agents = [TestAgent(i, model) for i in range(10)]
+    _ = [TestAgent(i, model) for i in range(10)]
 
     agentset = model.agents
 
+    agentset.set("a", 5)
+    agentset.set("b", 6)
+
+    values = agentset.get(["a", "b"])
+    assert all([(a == 5) & (b == 6) for a,b in values])
+
     with pytest.raises(AttributeError):
         agentset.get("unknown_attribute")
 
-    results = agentset.get("unknown_attribute", True)
+    results = agentset.get("unknown_attribute", handle_missing="default", default_value=True)
     assert all(results) is True
 
+    values = agentset.get(["a", "unknown_attribute"], handle_missing="default", default_value=True)
+    assert all([(a == 5) & (b == True) for a,b in values])
+
+    results = agentset.get("unknown_attribute", handle_missing="skip")
+    assert len(results) == 0
+
+    values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
+    assert all([(a == 5) for a, in values])
+
+    with pytest.raises(ValueError):
+        agentset.get("unknown_attribute", handle_missing="some nonsense value")
+
 
 def test_agentset_agg():
     model = Model()

From 8bc05b16a56190a37b17852ee863ef1e4b1f01fb Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 5 Sep 2024 12:03:51 +0000
Subject: [PATCH 07/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 mesa/agent.py       | 47 ++++++++++++++++++++++++++++++++++++---------
 tests/test_agent.py | 14 +++++++++-----
 2 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 375baeaceba..9cd38a8e1bd 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -348,7 +348,12 @@ def agg(self, attribute: str, func: Callable) -> Any:
         values = self.get(attribute)
         return func(values)
 
-    def get(self, attr_names: str | list[str], handle_missing: str = "error", default_value: Any = None) -> list[Any] | list[list[Any]]:
+    def get(
+        self,
+        attr_names: str | list[str],
+        handle_missing: str = "error",
+        default_value: Any = None,
+    ) -> list[Any] | list[list[Any]]:
         """
         Retrieve the specified attribute(s) from each agent in the AgentSet.
 
@@ -379,28 +384,52 @@ def get(self, attr_names: str | list[str], handle_missing: str = "error", defaul
         match handle_missing:
             case "error":
                 if is_single_attr:
-                    return [self._get_or_raise(agent, attr_names) for agent in self._agents]
+                    return [
+                        self._get_or_raise(agent, attr_names) for agent in self._agents
+                    ]
                 else:
-                    return [[self._get_or_raise(agent, attr) for attr in attr_names] for agent in self._agents]
+                    return [
+                        [self._get_or_raise(agent, attr) for attr in attr_names]
+                        for agent in self._agents
+                    ]
 
             case "default":
                 if is_single_attr:
-                    return [self._get_with_default(agent, attr_names, default_value) for agent in self._agents]
+                    return [
+                        self._get_with_default(agent, attr_names, default_value)
+                        for agent in self._agents
+                    ]
                 else:
-                    return [[self._get_with_default(agent, attr, default_value) for attr in attr_names] for agent in self._agents]
+                    return [
+                        [
+                            self._get_with_default(agent, attr, default_value)
+                            for attr in attr_names
+                        ]
+                        for agent in self._agents
+                    ]
 
             case "skip":
                 if is_single_attr:
-                    return [val for agent in self._agents if (val := self._get_skip(agent, attr_names)) is not None]
+                    return [
+                        val
+                        for agent in self._agents
+                        if (val := self._get_skip(agent, attr_names)) is not None
+                    ]
                 else:
                     return [
-                        [val for attr in attr_names if (val := self._get_skip(agent, attr)) is not None]
+                        [
+                            val
+                            for attr in attr_names
+                            if (val := self._get_skip(agent, attr)) is not None
+                        ]
                         for agent in self._agents
                     ]
 
             case _:
-                raise ValueError(f"Unknown handle_missing option: {handle_missing}, "
-                                 "should be one of 'error', 'skip', or 'default'")
+                raise ValueError(
+                    f"Unknown handle_missing option: {handle_missing}, "
+                    "should be one of 'error', 'skip', or 'default'"
+                )
 
     # Helper method to get an attribute or raise an error if it's missing
     def _get_or_raise(self, agent: Any, attr_name: str) -> Any:
diff --git a/tests/test_agent.py b/tests/test_agent.py
index e201f846b49..f3913b80b8a 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -286,22 +286,26 @@ def test_agentset_get():
     agentset.set("b", 6)
 
     values = agentset.get(["a", "b"])
-    assert all([(a == 5) & (b == 6) for a,b in values])
+    assert all([(a == 5) & (b == 6) for a, b in values])
 
     with pytest.raises(AttributeError):
         agentset.get("unknown_attribute")
 
-    results = agentset.get("unknown_attribute", handle_missing="default", default_value=True)
+    results = agentset.get(
+        "unknown_attribute", handle_missing="default", default_value=True
+    )
     assert all(results) is True
 
-    values = agentset.get(["a", "unknown_attribute"], handle_missing="default", default_value=True)
-    assert all([(a == 5) & (b == True) for a,b in values])
+    values = agentset.get(
+        ["a", "unknown_attribute"], handle_missing="default", default_value=True
+    )
+    assert all([(a == 5) & (b == True) for a, b in values])
 
     results = agentset.get("unknown_attribute", handle_missing="skip")
     assert len(results) == 0
 
     values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
-    assert all([(a == 5) for a, in values])
+    assert all([(a == 5) for (a,) in values])
 
     with pytest.raises(ValueError):
         agentset.get("unknown_attribute", handle_missing="some nonsense value")

From 713373a925cb945a2f825c89eb20b132249955e5 Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Thu, 5 Sep 2024 14:06:27 +0200
Subject: [PATCH 08/16] ruff related fixes

---
 tests/test_agent.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/tests/test_agent.py b/tests/test_agent.py
index f3913b80b8a..8486035b377 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -286,7 +286,7 @@ def test_agentset_get():
     agentset.set("b", 6)
 
     values = agentset.get(["a", "b"])
-    assert all([(a == 5) & (b == 6) for a, b in values])
+    assert all((a == 5) & (b == 6) for a,b in values)
 
     with pytest.raises(AttributeError):
         agentset.get("unknown_attribute")
@@ -296,16 +296,14 @@ def test_agentset_get():
     )
     assert all(results) is True
 
-    values = agentset.get(
-        ["a", "unknown_attribute"], handle_missing="default", default_value=True
-    )
-    assert all([(a == 5) & (b == True) for a, b in values])
+    values = agentset.get(["a", "unknown_attribute"], handle_missing="default", default_value=True)
+    assert all((a == 5) & b for a,b in values)
 
     results = agentset.get("unknown_attribute", handle_missing="skip")
     assert len(results) == 0
 
     values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
-    assert all([(a == 5) for (a,) in values])
+    assert all((a == 5) for a, in values)
 
     with pytest.raises(ValueError):
         agentset.get("unknown_attribute", handle_missing="some nonsense value")

From 81c4a6df1b148cb21fb7c4c7e7bbbb32ccdf7dc1 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 5 Sep 2024 12:07:29 +0000
Subject: [PATCH 09/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 tests/test_agent.py | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/tests/test_agent.py b/tests/test_agent.py
index 8486035b377..4aac00be646 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -286,7 +286,7 @@ def test_agentset_get():
     agentset.set("b", 6)
 
     values = agentset.get(["a", "b"])
-    assert all((a == 5) & (b == 6) for a,b in values)
+    assert all((a == 5) & (b == 6) for a, b in values)
 
     with pytest.raises(AttributeError):
         agentset.get("unknown_attribute")
@@ -296,14 +296,16 @@ def test_agentset_get():
     )
     assert all(results) is True
 
-    values = agentset.get(["a", "unknown_attribute"], handle_missing="default", default_value=True)
-    assert all((a == 5) & b for a,b in values)
+    values = agentset.get(
+        ["a", "unknown_attribute"], handle_missing="default", default_value=True
+    )
+    assert all((a == 5) & b for a, b in values)
 
     results = agentset.get("unknown_attribute", handle_missing="skip")
     assert len(results) == 0
 
     values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
-    assert all((a == 5) for a, in values)
+    assert all((a == 5) for (a,) in values)
 
     with pytest.raises(ValueError):
         agentset.get("unknown_attribute", handle_missing="some nonsense value")

From 721884cdc48ca1a6e3063e197b039f67096dc1fc Mon Sep 17 00:00:00 2001
From: Ewout ter Hoeven <E.M.terHoeven@student.tudelft.nl>
Date: Thu, 5 Sep 2024 19:03:36 +0200
Subject: [PATCH 10/16] test_agent.py: Add some more cases for get

---
 tests/test_agent.py | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/tests/test_agent.py b/tests/test_agent.py
index 4aac00be646..876bb47a70b 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -285,31 +285,59 @@ def test_agentset_get():
     agentset.set("a", 5)
     agentset.set("b", 6)
 
+    # Case 1: Normal retrieval of existing attributes
     values = agentset.get(["a", "b"])
     assert all((a == 5) & (b == 6) for a, b in values)
 
+    # Case 2: Raise AttributeError when attribute doesn't exist
     with pytest.raises(AttributeError):
         agentset.get("unknown_attribute")
 
+    # Case 3: Use default value when attribute is missing
     results = agentset.get(
         "unknown_attribute", handle_missing="default", default_value=True
     )
     assert all(results) is True
 
+    # Case 4: Retrieve mixed attributes with default value for missing ones
     values = agentset.get(
         ["a", "unknown_attribute"], handle_missing="default", default_value=True
     )
     assert all((a == 5) & b for a, b in values)
 
+    # Case 5: Skip agents missing the attribute
     results = agentset.get("unknown_attribute", handle_missing="skip")
     assert len(results) == 0
 
+    # Case 6: Skip missing attributes in mixed attribute retrieval
     values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
     assert all((a == 5) for (a,) in values)
 
+    # Case 7: Invalid handle_missing value raises ValueError
     with pytest.raises(ValueError):
         agentset.get("unknown_attribute", handle_missing="some nonsense value")
 
+    # Case 8: Retrieve multiple attributes with mixed existence and 'default' handling
+    values = agentset.get(
+        ["a", "b", "unknown_attribute"], handle_missing="default", default_value=0
+    )
+    assert all((a == 5) & (b == 6) & (unknown == 0) for a, b, unknown in values)
+
+    # Case 9: Retrieve multiple attributes with 'skip' handling for missing attributes
+    values = agentset.get(["a", "b", "unknown_attribute"], handle_missing="skip")
+    assert all((a == 5) & (b == 6) for a, b in values)  # No unknown_attribute included
+
+    # Case 10: 'default' handling when one attribute is completely missing from some agents
+    agentset.set("c", 8)  # Only some agents have attribute 'c'
+    values = agentset.get(
+        ["a", "c"], handle_missing="default", default_value=-1
+    )
+    assert all((a == 5) & (c in [8, -1]) for a, c in values)
+
+    # Case 11: Skip handling when one attribute is completely missing from some agents
+    values = agentset.get(["a", "c"], handle_missing="skip")
+    assert all(a == 5 for (a,) in values)  # Only agents with 'a' are returned
+
 
 def test_agentset_agg():
     model = Model()

From 73d9346b75e228a0b68a200092f909110f83cb02 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 5 Sep 2024 17:03:42 +0000
Subject: [PATCH 11/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 tests/test_agent.py | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tests/test_agent.py b/tests/test_agent.py
index 876bb47a70b..b119a224904 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -329,9 +329,7 @@ def test_agentset_get():
 
     # Case 10: 'default' handling when one attribute is completely missing from some agents
     agentset.set("c", 8)  # Only some agents have attribute 'c'
-    values = agentset.get(
-        ["a", "c"], handle_missing="default", default_value=-1
-    )
+    values = agentset.get(["a", "c"], handle_missing="default", default_value=-1)
     assert all((a == 5) & (c in [8, -1]) for a, c in values)
 
     # Case 11: Skip handling when one attribute is completely missing from some agents

From bd20fa657587dabb40d65fad132e2af579e65815 Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Thu, 5 Sep 2024 22:41:02 +0200
Subject: [PATCH 12/16] Update mesa/agent.py

Co-authored-by: Corvince <13568919+Corvince@users.noreply.github.com>
---
 mesa/agent.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 9cd38a8e1bd..5508830beeb 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -351,7 +351,7 @@ def agg(self, attribute: str, func: Callable) -> Any:
     def get(
         self,
         attr_names: str | list[str],
-        handle_missing: str = "error",
+        handle_missing: Literal["error", "skip", "default"] = "error",
         default_value: Any = None,
     ) -> list[Any] | list[list[Any]]:
         """

From 507e2525a1ec97e6da6f4449d94fd02274373c66 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 5 Sep 2024 20:42:47 +0000
Subject: [PATCH 13/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 mesa/agent.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 5508830beeb..970b03dae60 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -351,7 +351,7 @@ def agg(self, attribute: str, func: Callable) -> Any:
     def get(
         self,
         attr_names: str | list[str],
-        handle_missing: Literal["error", "skip", "default"] = "error",
+        handle_missing: Literal[error, skip, default] = "error",
         default_value: Any = None,
     ) -> list[Any] | list[list[Any]]:
         """

From 576a389a8e98cb35c79e50701621c8ee05ca44b4 Mon Sep 17 00:00:00 2001
From: Ewout ter Hoeven <E.M.terHoeven@student.tudelft.nl>
Date: Fri, 6 Sep 2024 10:33:25 +0200
Subject: [PATCH 14/16] Update get bug and tests

---
 mesa/agent.py       | 126 ++++++++++++++++++--------------------------
 tests/test_agent.py |   6 +--
 2 files changed, 53 insertions(+), 79 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 970b03dae60..19bbc5b052f 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -20,7 +20,7 @@
 from random import Random
 
 # mypy
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, Literal
 
 if TYPE_CHECKING:
     # We ensure that these are not imported during runtime to prevent cyclic
@@ -351,7 +351,7 @@ def agg(self, attribute: str, func: Callable) -> Any:
     def get(
         self,
         attr_names: str | list[str],
-        handle_missing: Literal[error, skip, default] = "error",
+        handle_missing: Literal["error", "skip", "default"] = "error",
         default_value: Any = None,
     ) -> list[Any] | list[list[Any]]:
         """
@@ -359,15 +359,12 @@ def get(
 
         Args:
             attr_names (str | list[str]): The name(s) of the attribute(s) to retrieve from each agent.
-            handle_missing (str, optional): How to handle missing attributes. Can be
-
-                                            -'error' (default), raises an AttributeError if attribute is missing.
-                                            -'skip' which skips the agents missing the attribute.
-                                            'default' to return the specified `default_value`.
-
-            default_value (Any, optional): Used in conjunction with ``handle_missing='default``
-                                     The default value to return if 'handle_missing' is set to 'default'
-                                     and the agent does not have the attribute.
+            handle_missing (str, optional): How to handle missing attributes. Can be:
+                                            - 'error' (default): raises an AttributeError if attribute is missing.
+                                            - 'skip': skips the agents missing the attribute.
+                                            - 'default': returns the specified default_value.
+            default_value (Any, optional): The default value to return if 'handle_missing' is set to 'default'
+                                           and the agent does not have the attribute.
 
         Returns:
             list[Any]: A list of attribute values for each agent if attr_names is a str.
@@ -375,76 +372,53 @@ def get(
 
         Raises:
             AttributeError: If 'handle_missing' is 'error' and the agent does not have the specified attribute(s).
+            ValueError: If an unknown 'handle_missing' option is provided.
         """
-
-        # Check if the attr_names is a single string or a list of attributes.
         is_single_attr = isinstance(attr_names, str)
 
-        # Branch earlier based on the `handle_missing` option to avoid repeated checks
-        match handle_missing:
-            case "error":
-                if is_single_attr:
-                    return [
-                        self._get_or_raise(agent, attr_names) for agent in self._agents
-                    ]
-                else:
-                    return [
-                        [self._get_or_raise(agent, attr) for attr in attr_names]
-                        for agent in self._agents
-                    ]
-
-            case "default":
-                if is_single_attr:
-                    return [
-                        self._get_with_default(agent, attr_names, default_value)
-                        for agent in self._agents
-                    ]
-                else:
-                    return [
-                        [
-                            self._get_with_default(agent, attr, default_value)
-                            for attr in attr_names
-                        ]
-                        for agent in self._agents
-                    ]
-
-            case "skip":
-                if is_single_attr:
-                    return [
-                        val
-                        for agent in self._agents
-                        if (val := self._get_skip(agent, attr_names)) is not None
-                    ]
-                else:
-                    return [
-                        [
-                            val
-                            for attr in attr_names
-                            if (val := self._get_skip(agent, attr)) is not None
-                        ]
-                        for agent in self._agents
+        if handle_missing == "error":
+            if is_single_attr:
+                return [getattr(agent, attr_names) for agent in self._agents]
+            else:
+                return [
+                    [getattr(agent, attr) for attr in attr_names]
+                    for agent in self._agents
+                ]
+
+        elif handle_missing == "default":
+            if is_single_attr:
+                return [
+                    getattr(agent, attr_names, default_value) for agent in self._agents
+                ]
+            else:
+                return [
+                    [getattr(agent, attr, default_value) for attr in attr_names]
+                    for agent in self._agents
+                ]
+
+        elif handle_missing == "skip":
+            if is_single_attr:
+                return [
+                    getattr(agent, attr_names)
+                    for agent in self._agents
+                    if hasattr(agent, attr_names)
+                ]
+            else:
+                return [
+                    [
+                        getattr(agent, attr)
+                        for attr in attr_names
+                        if hasattr(agent, attr)
                     ]
+                    for agent in self._agents
+                    if any(hasattr(agent, attr) for attr in attr_names)
+                ]
 
-            case _:
-                raise ValueError(
-                    f"Unknown handle_missing option: {handle_missing}, "
-                    "should be one of 'error', 'skip', or 'default'"
-                )
-
-    # Helper method to get an attribute or raise an error if it's missing
-    def _get_or_raise(self, agent: Any, attr_name: str) -> Any:
-        return getattr(agent, attr_name)
-
-    # Helper method to get an attribute with a default value if missing
-    def _get_with_default(self, agent: Any, attr_name: str, default: Any) -> Any:
-        return getattr(agent, attr_name, default)
-
-    # Helper method to skip missing attributes by returning None
-    def _get_skip(self, agent: Any, attr_name: str) -> Any:
-        try:
-            return getattr(agent, attr_name)
-        except AttributeError:
-            return None
+        else:
+            raise ValueError(
+                f"Unknown handle_missing option: {handle_missing}, "
+                "should be one of 'error', 'skip', or 'default'"
+            )
 
     def set(self, attr_name: str, value: Any) -> AgentSet:
         """
diff --git a/tests/test_agent.py b/tests/test_agent.py
index b119a224904..195a3fe44d5 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -303,7 +303,7 @@ def test_agentset_get():
     values = agentset.get(
         ["a", "unknown_attribute"], handle_missing="default", default_value=True
     )
-    assert all((a == 5) & b for a, b in values)
+    assert all((a == 5) & (unknown is True) for a, unknown in values)
 
     # Case 5: Skip agents missing the attribute
     results = agentset.get("unknown_attribute", handle_missing="skip")
@@ -328,13 +328,13 @@ def test_agentset_get():
     assert all((a == 5) & (b == 6) for a, b in values)  # No unknown_attribute included
 
     # Case 10: 'default' handling when one attribute is completely missing from some agents
-    agentset.set("c", 8)  # Only some agents have attribute 'c'
+    agentset.select(at_most=0.5).set("c", 8)  # Only some agents have attribute 'c'
     values = agentset.get(["a", "c"], handle_missing="default", default_value=-1)
     assert all((a == 5) & (c in [8, -1]) for a, c in values)
 
     # Case 11: Skip handling when one attribute is completely missing from some agents
     values = agentset.get(["a", "c"], handle_missing="skip")
-    assert all(a == 5 for (a,) in values)  # Only agents with 'a' are returned
+    assert all(5 in a for a in values)  # Only agents with 'a' are returned
 
 
 def test_agentset_agg():

From b623cd1f72e065a3db6d9eb119d187b7b8652c51 Mon Sep 17 00:00:00 2001
From: Jan Kwakkel <j.h.kwakkel@tudelft.nl>
Date: Fri, 6 Sep 2024 16:04:53 +0200
Subject: [PATCH 15/16] remove skip and update tests

---
 mesa/agent.py       | 27 ++++-----------------------
 tests/test_agent.py | 21 +++------------------
 2 files changed, 7 insertions(+), 41 deletions(-)

diff --git a/mesa/agent.py b/mesa/agent.py
index 19bbc5b052f..5816ddf060a 100644
--- a/mesa/agent.py
+++ b/mesa/agent.py
@@ -351,7 +351,7 @@ def agg(self, attribute: str, func: Callable) -> Any:
     def get(
         self,
         attr_names: str | list[str],
-        handle_missing: Literal["error", "skip", "default"] = "error",
+        handle_missing: Literal["error", "default"] = "error",
         default_value: Any = None,
     ) -> list[Any] | list[list[Any]]:
         """
@@ -361,14 +361,13 @@ def get(
             attr_names (str | list[str]): The name(s) of the attribute(s) to retrieve from each agent.
             handle_missing (str, optional): How to handle missing attributes. Can be:
                                             - 'error' (default): raises an AttributeError if attribute is missing.
-                                            - 'skip': skips the agents missing the attribute.
                                             - 'default': returns the specified default_value.
             default_value (Any, optional): The default value to return if 'handle_missing' is set to 'default'
                                            and the agent does not have the attribute.
 
         Returns:
-            list[Any]: A list of attribute values for each agent if attr_names is a str.
-            list[list[Any]]: A list of lists of attribute values for each agent if attr_names is a list of str.
+            list[Any]: A list with the attribute value for each agent if attr_names is a str.
+            list[list[Any]]: A list with a lists of attribute values for each agent if attr_names is a list of str.
 
         Raises:
             AttributeError: If 'handle_missing' is 'error' and the agent does not have the specified attribute(s).
@@ -396,28 +395,10 @@ def get(
                     for agent in self._agents
                 ]
 
-        elif handle_missing == "skip":
-            if is_single_attr:
-                return [
-                    getattr(agent, attr_names)
-                    for agent in self._agents
-                    if hasattr(agent, attr_names)
-                ]
-            else:
-                return [
-                    [
-                        getattr(agent, attr)
-                        for attr in attr_names
-                        if hasattr(agent, attr)
-                    ]
-                    for agent in self._agents
-                    if any(hasattr(agent, attr) for attr in attr_names)
-                ]
-
         else:
             raise ValueError(
                 f"Unknown handle_missing option: {handle_missing}, "
-                "should be one of 'error', 'skip', or 'default'"
+                "should be one of 'error' or 'default'"
             )
 
     def set(self, attr_name: str, value: Any) -> AgentSet:
diff --git a/tests/test_agent.py b/tests/test_agent.py
index 195a3fe44d5..3438776a83d 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -305,36 +305,21 @@ def test_agentset_get():
     )
     assert all((a == 5) & (unknown is True) for a, unknown in values)
 
-    # Case 5: Skip agents missing the attribute
-    results = agentset.get("unknown_attribute", handle_missing="skip")
-    assert len(results) == 0
-
-    # Case 6: Skip missing attributes in mixed attribute retrieval
-    values = agentset.get(["a", "unknown_attribute"], handle_missing="skip")
-    assert all((a == 5) for (a,) in values)
-
-    # Case 7: Invalid handle_missing value raises ValueError
+    # Case 5: Invalid handle_missing value raises ValueError
     with pytest.raises(ValueError):
         agentset.get("unknown_attribute", handle_missing="some nonsense value")
 
-    # Case 8: Retrieve multiple attributes with mixed existence and 'default' handling
+    # Case 6: Retrieve multiple attributes with mixed existence and 'default' handling
     values = agentset.get(
         ["a", "b", "unknown_attribute"], handle_missing="default", default_value=0
     )
     assert all((a == 5) & (b == 6) & (unknown == 0) for a, b, unknown in values)
 
-    # Case 9: Retrieve multiple attributes with 'skip' handling for missing attributes
-    values = agentset.get(["a", "b", "unknown_attribute"], handle_missing="skip")
-    assert all((a == 5) & (b == 6) for a, b in values)  # No unknown_attribute included
-
-    # Case 10: 'default' handling when one attribute is completely missing from some agents
+    # Case 7: 'default' handling when one attribute is completely missing from some agents
     agentset.select(at_most=0.5).set("c", 8)  # Only some agents have attribute 'c'
     values = agentset.get(["a", "c"], handle_missing="default", default_value=-1)
     assert all((a == 5) & (c in [8, -1]) for a, c in values)
 
-    # Case 11: Skip handling when one attribute is completely missing from some agents
-    values = agentset.get(["a", "c"], handle_missing="skip")
-    assert all(5 in a for a in values)  # Only agents with 'a' are returned
 
 
 def test_agentset_agg():

From 9d33f687c5b502e6e72c0639b341bb863ab94ec8 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
 <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Fri, 6 Sep 2024 14:05:02 +0000
Subject: [PATCH 16/16] [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci
---
 tests/test_agent.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/test_agent.py b/tests/test_agent.py
index 3438776a83d..787cfc0bc75 100644
--- a/tests/test_agent.py
+++ b/tests/test_agent.py
@@ -321,7 +321,6 @@ def test_agentset_get():
     assert all((a == 5) & (c in [8, -1]) for a, c in values)
 
 
-
 def test_agentset_agg():
     model = Model()
     agents = [TestAgent(model) for i in range(10)]