upgrade code to pyhon 3.8 and xarray 2022.03 (#367)

mesmer/__init__.py

@@ -7,6 +7,8 @@
 analyze the results.
 """
 
+from importlib.metadata import version as _get_version
+
 from . import calibrate_mesmer, core, create_emulations, io, stats, testing, utils
 from .core import _data as data
 from .core import geospatial, grid, mask, volc, weighted
@@ -32,13 +34,6 @@
     "weighted",
 ]
 
-try:
-    from importlib.metadata import version as _get_version
-except ImportError:
-    # importlib.metadata not available in python 3.7
-    import pkg_resources
-
-    _get_version = lambda pkg: pkg_resources.get_distribution(pkg).version
 
 try:
     __version__ = _get_version("mesmer-emulator")

mesmer/stats/_auto_regression.py

@@ -1,7 +1,6 @@
 import numpy as np
 import pandas as pd
 import xarray as xr
-from packaging.version import Version
 
 from mesmer.core.utils import _check_dataarray_form, _check_dataset_form
 
@@ -36,23 +35,18 @@ def _select_ar_order_scen_ens(*objs, dim, ens_dim, maxlag, ic="bic"):
     then over all scenarios.
     """
 
-    if Version(xr.__version__) >= Version("2022.03.0"):
-        method = "method"
-    else:
-        method = "interpolation"
-
     ar_order_scen = list()
     for obj in objs:
         res = select_ar_order(obj, dim=dim, maxlag=maxlag, ic=ic)
 
         if ens_dim in res.dims:
-            res = res.quantile(dim=ens_dim, q=0.5, **{method: "nearest"})
+            res = res.quantile(dim=ens_dim, q=0.5, method="nearest")
 
         ar_order_scen.append(res)
 
     ar_order_scen = xr.concat(ar_order_scen, dim="scen")
 
-    ar_order = ar_order_scen.quantile(0.5, dim="scen", **{method: "nearest"})
+    ar_order = ar_order_scen.quantile(0.5, dim="scen", method="nearest")
 
     if not np.isnan(ar_order).any():
         ar_order = ar_order.astype(int)

tests/unit/test_smoothing.py

@@ -2,7 +2,6 @@
 import pandas as pd
 import pytest
 import xarray as xr
-from packaging.version import Version
 from statsmodels.nonparametric.smoothers_lowess import lowess
 
 import mesmer
@@ -35,15 +34,12 @@ def test_lowess_errors():
     with pytest.raises(TypeError, match="Cannot convert coords"):
         mesmer.stats.lowess(data.to_dataset(), "time", frac=0.5)
 
-    # TODO: remove check once we drop python 3.7
-    if Version(xr.__version__) >= Version("21.0"):
-
-        # cftime datetime
-        time = xr.date_range("2000-01-01", periods=30, calendar="noleap")
-        data = data.assign_coords(time=time)
+    # cftime datetime
+    time = xr.date_range("2000-01-01", periods=30, calendar="noleap")
+    data = data.assign_coords(time=time)
 
-        with pytest.raises(TypeError, match="Cannot convert coords"):
-            mesmer.stats.lowess(data.to_dataset(), "time", frac=0.5)
+    with pytest.raises(TypeError, match="Cannot convert coords"):
+        mesmer.stats.lowess(data.to_dataset(), "time", frac=0.5)
 
 
 @pytest.mark.parametrize("it", [0, 3])
@@ -171,19 +167,16 @@ def test_lowess_2D_combine_dim():
 
     xr.testing.assert_allclose(expected, result)
 
-    # TODO: remove check once we drop python 3.7
-    if Version(xr.__version__) >= Version("21.0"):
-
-        # cftime datetime
-        time = xr.date_range("2000-01-01", periods=30, calendar="noleap")
-        data = data.assign_coords(time=time)
+    # cftime datetime
+    time = xr.date_range("2000-01-01", periods=30, calendar="noleap")
+    data = data.assign_coords(time=time)
 
-        result = mesmer.stats.lowess(
-            data, "time", combine_dim="cells", frac=0.3, use_coords=False
-        )
-        expected = expected.assign_coords(time=time)
+    result = mesmer.stats.lowess(
+        data, "time", combine_dim="cells", frac=0.3, use_coords=False
+    )
+    expected = expected.assign_coords(time=time)
 
-        xr.testing.assert_allclose(expected, result)
+    xr.testing.assert_allclose(expected, result)
 
 
 def test_lowess_2D_combine_dim_it():