fixed #98 (enum not considered immutable)

src/frozendict/cool.py

@@ -2,7 +2,7 @@
 from array import array
 from frozendict import frozendict
 from collections.abc import MutableMapping, MutableSequence, MutableSet
-
+from enum import Enum
 
 # fix for python 3.9-
 
@@ -32,11 +32,16 @@ def getItems(o):
     return enumerate
 
 
+def nil(x):
+    return x
+
+
 _freeze_conversion_map = frozendict({
     MutableMapping: frozendict, 
     bytearray: bytes, 
     MutableSequence: tuple, 
     MutableSet: frozenset,
+    Enum: nil,
 })
 
 _freeze_conversion_map_custom = {}
@@ -317,3 +322,4 @@ def deepfreeze(
 del MutableMapping
 del MutableSequence
 del MutableSet
+del Enum

test/test_freeze.py

@@ -6,6 +6,7 @@
 from array import array
 from types import MappingProxyType
 from frozendict import FreezeError, FreezeWarning
+from enum import Enum
 
 
 class A:
@@ -98,6 +99,10 @@ def after_cure():
 def after_cure_a(a):
     return custom_a_converter(a)
 
+@pytest.fixture
+def my_enum():
+    Color = Enum('Color', ['RED', 'GREEN', 'BLUE'])
+    return Color.RED
 
 def test_deepfreeze(before_cure, after_cure):
     assert cool.deepfreeze(before_cure) == after_cure
@@ -193,3 +198,7 @@ def test_original_immutate():
     frozen = cool.deepfreeze(unfrozen)
 
     assert type(unfrozen["nested"]) is dict
+
+
+def test_enum(my_enum):
+    assert cool.deepfreeze(my_enum) is my_enum