Closes #114

Author: sobolevn

returns/converters.py

@@ -32,18 +32,18 @@ def join(container: IO[IO[_ValueType]]) -> IO[_ValueType]:
     """Case for ``IO`` container."""
 
 
-@overload  # noqa: WPS440
+@overload
 def join(container: Maybe[Maybe[_ValueType]]) -> Maybe[_ValueType]:
     """Case for ``Maybe`` container."""
 
 
-@overload  # noqa: WPS440
+@overload
 def join(
     container: Result[Result[_ValueType, _ErrorType], _ErrorType],
 ) -> Result[_ValueType, _ErrorType]:
     """Case for ``Result`` container."""
 
 
-def join(container):  # noqa: WPS440
+def join(container):
     """Joins two nested containers together."""
     return container._inner_value  # noqa: WPS437

returns/primitives/container.py

@@ -48,6 +48,10 @@ def __eq__(self, other) -> bool:
             return False
         return self._inner_value == other._inner_value  # noqa: WPS437
 
+    def __hash__(self) -> int:
+        """Used to use this value as a key."""
+        return hash(self._inner_value)
+
 
 @runtime
 class Bindable(Protocol[_ValueType]):

tests/test_maybe/test_maybe_equality.py

@@ -32,9 +32,10 @@ def test_protocols(container, protocol):
 def test_equality():
     """Ensures that containers can be compared."""
     assert Nothing is Nothing  # noqa: WPS312
-    assert Nothing == _Nothing() == _Nothing(None)
+    assert Nothing == _Nothing() == _Nothing(None) == Some(None)
     assert Some(5) == Some(5)
-    assert Some(None) == Nothing
+    assert hash(Some(1))
+    assert hash(Nothing)
 
 
 def test_nonequality():

tests/test_result/test_result_equality.py

@@ -38,6 +38,8 @@ def test_nonequality():
     assert Failure(input_value) != input_value
     assert Success(input_value) != input_value
     assert Failure(input_value) != Success(input_value)
+    assert hash(Failure(1))
+    assert hash(Success(1))
 
 
 def test_is_compare():