diff --git a/lib/yaml/__init__.py b/lib/yaml/__init__.py
index 48b33b3c..b0826a51 100644
--- a/lib/yaml/__init__.py
+++ b/lib/yaml/__init__.py
@@ -335,7 +335,7 @@ def add_constructor(tag, constructor, Loader=None):
     Constructor is a function that accepts a Loader instance
     and a node object and produces the corresponding Python object.
     """
-    if Loader == None:
+    if Loader is None:
         loader.Loader.add_constructor(tag, constructor)
         loader.FullLoader.add_constructor(tag, constructor)
         loader.UnsafeLoader.add_constructor(tag, constructor)
@@ -349,7 +349,7 @@ def add_multi_constructor(tag_prefix, multi_constructor, Loader=None):
     Multi-constructor accepts a Loader instance, a tag suffix,
     and a node object and produces the corresponding Python object.
     """
-    if Loader == None:
+    if Loader is None:
         loader.Loader.add_multi_constructor(tag_prefix, multi_constructor)
         loader.FullLoader.add_multi_constructor(tag_prefix, multi_constructor)
         loader.UnsafeLoader.add_multi_constructor(tag_prefix, multi_constructor)
diff --git a/lib3/yaml/__init__.py b/lib3/yaml/__init__.py
index 183969e5..52272a90 100644
--- a/lib3/yaml/__init__.py
+++ b/lib3/yaml/__init__.py
@@ -332,7 +332,7 @@ def add_constructor(tag, constructor, Loader=None):
     Constructor is a function that accepts a Loader instance
     and a node object and produces the corresponding Python object.
     """
-    if Loader == None:
+    if Loader is None:
         loader.Loader.add_constructor(tag, constructor)
         loader.FullLoader.add_constructor(tag, constructor)
         loader.UnsafeLoader.add_constructor(tag, constructor)
@@ -346,7 +346,7 @@ def add_multi_constructor(tag_prefix, multi_constructor, Loader=None):
     Multi-constructor accepts a Loader instance, a tag suffix,
     and a node object and produces the corresponding Python object.
     """
-    if Loader == None:
+    if Loader is None:
         loader.Loader.add_multi_constructor(tag_prefix, multi_constructor)
         loader.FullLoader.add_multi_constructor(tag_prefix, multi_constructor)
         loader.UnsafeLoader.add_multi_constructor(tag_prefix, multi_constructor)