fmap always returns immutable object

NSArray+map.m

@@ -28,11 +28,7 @@ @implementation NSArray (YOLO)
             if (o)
                 mapped[jj++] = o;
         }
-
-        Class immutableClass = [NSArray class];
-        Class mutableClass = [NSMutableArray class];
-        Class cls = [self isKindOfClass:mutableClass] ? mutableClass : immutableClass;
-        return [[cls alloc] initWithObjects:mapped count:jj];
+        return [NSArray arrayWithObjects:mapped count:jj];
     };
 }
 

NSDictionary+fmap.m

@@ -25,7 +25,7 @@ @implementation NSDictionary (YOLO)
                 objs[ii++] = o;
             }
         }
-        return [[self.class alloc] initWithObjects:objs forKeys:keys count:ii];
+        return [NSDictionary dictionaryWithObjects:objs forKeys:keys count:ii];
     };
 }
 

NSSet+fmap.m

@@ -11,7 +11,7 @@ @implementation NSSet (YOLO)
             if (o)
                 mapped[ii++] = o;
         }
-        return [[self.class alloc] initWithObjects:mapped count:ii];
+        return [NSSet setWithObjects:mapped count:ii];
     };
 }