diff --git a/modules/swagger-codegen/src/main/resources/python/model.mustache b/modules/swagger-codegen/src/main/resources/python/model.mustache
index d7c3493d9da..bd33a997c3e 100644
--- a/modules/swagger-codegen/src/main/resources/python/model.mustache
+++ b/modules/swagger-codegen/src/main/resources/python/model.mustache
@@ -95,13 +95,14 @@ class {{classname}}(object):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value
 
diff --git a/samples/client/petstore/python/swagger_client/models/category.py b/samples/client/petstore/python/swagger_client/models/category.py
index 59970e0bc3f..b8d540c51bd 100644
--- a/samples/client/petstore/python/swagger_client/models/category.py
+++ b/samples/client/petstore/python/swagger_client/models/category.py
@@ -106,13 +106,14 @@ def to_dict(self):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value
 
diff --git a/samples/client/petstore/python/swagger_client/models/order.py b/samples/client/petstore/python/swagger_client/models/order.py
index 488f01f05ba..4c8911f267b 100644
--- a/samples/client/petstore/python/swagger_client/models/order.py
+++ b/samples/client/petstore/python/swagger_client/models/order.py
@@ -212,13 +212,14 @@ def to_dict(self):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value
 
diff --git a/samples/client/petstore/python/swagger_client/models/pet.py b/samples/client/petstore/python/swagger_client/models/pet.py
index 94ca2249c0a..dfa614b1e9b 100644
--- a/samples/client/petstore/python/swagger_client/models/pet.py
+++ b/samples/client/petstore/python/swagger_client/models/pet.py
@@ -212,13 +212,14 @@ def to_dict(self):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value
 
diff --git a/samples/client/petstore/python/swagger_client/models/tag.py b/samples/client/petstore/python/swagger_client/models/tag.py
index 4deced8a351..50f829d65e3 100644
--- a/samples/client/petstore/python/swagger_client/models/tag.py
+++ b/samples/client/petstore/python/swagger_client/models/tag.py
@@ -106,13 +106,14 @@ def to_dict(self):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value
 
diff --git a/samples/client/petstore/python/swagger_client/models/user.py b/samples/client/petstore/python/swagger_client/models/user.py
index f8c1012842a..fd6d16824b3 100644
--- a/samples/client/petstore/python/swagger_client/models/user.py
+++ b/samples/client/petstore/python/swagger_client/models/user.py
@@ -256,13 +256,14 @@ def to_dict(self):
                     lambda x: x.to_dict() if hasattr(x, "to_dict") else x,
                     value
                 ))
+            elif hasattr(value, "to_dict"):
+                result[attr] = value.to_dict()
             elif isinstance(value, dict):
                 result[attr] = dict(map(
-                    lambda k, v: (k, v.to_dict()) if hasattr(v, "to_dict") else (k, v),
-                    value.iteritems()
+                    lambda item: (item[0], item[1].to_dict())
+                    if hasattr(item[1], "to_dict") else item,
+                    value.items()
                 ))
-            elif hasattr(value, "to_dict"):
-                result[attr] = value.to_dict()
             else:
                 result[attr] = value