diff --git a/modules/openapi-generator/src/main/resources/python/rest.mustache b/modules/openapi-generator/src/main/resources/python/rest.mustache
index 67ab8fa05f15..21c8d5b44c0b 100644
--- a/modules/openapi-generator/src/main/resources/python/rest.mustache
+++ b/modules/openapi-generator/src/main/resources/python/rest.mustache
@@ -137,7 +137,7 @@ class RESTClientObject(object):
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)
diff --git a/samples/client/petstore/python/petstore_api/rest.py b/samples/client/petstore/python/petstore_api/rest.py
index 313b06c1008a..a38fcec1c842 100644
--- a/samples/client/petstore/python/petstore_api/rest.py
+++ b/samples/client/petstore/python/petstore_api/rest.py
@@ -145,7 +145,7 @@ def request(self, method, url, query_params=None, headers=None,
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)
diff --git a/samples/client/petstore/python_disallowAdditionalPropertiesIfNotPresent/petstore_api/rest.py b/samples/client/petstore/python_disallowAdditionalPropertiesIfNotPresent/petstore_api/rest.py
index 313b06c1008a..a38fcec1c842 100644
--- a/samples/client/petstore/python_disallowAdditionalPropertiesIfNotPresent/petstore_api/rest.py
+++ b/samples/client/petstore/python_disallowAdditionalPropertiesIfNotPresent/petstore_api/rest.py
@@ -145,7 +145,7 @@ def request(self, method, url, query_params=None, headers=None,
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/rest.py b/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/rest.py
index 037c05442e8e..a7c5fd3304a1 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/rest.py
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/python/x_auth_id_alias/rest.py
@@ -145,7 +145,7 @@ def request(self, method, url, query_params=None, headers=None,
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)
diff --git a/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/rest.py b/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/rest.py
index 745549315b80..191d850b87d6 100644
--- a/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/rest.py
+++ b/samples/openapi3/client/features/dynamic-servers/python/dynamic_servers/rest.py
@@ -145,7 +145,7 @@ def request(self, method, url, query_params=None, headers=None,
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)
diff --git a/samples/openapi3/client/petstore/python/petstore_api/rest.py b/samples/openapi3/client/petstore/python/petstore_api/rest.py
index 313b06c1008a..a38fcec1c842 100644
--- a/samples/openapi3/client/petstore/python/petstore_api/rest.py
+++ b/samples/openapi3/client/petstore/python/petstore_api/rest.py
@@ -145,7 +145,7 @@ def request(self, method, url, query_params=None, headers=None,
                     headers['Content-Type'] = 'application/json'
                 if query_params:
                     url += '?' + urlencode(query_params)
-                if re.search('json', headers['Content-Type'], re.IGNORECASE):
+                if ('Content-Type' not in headers) or (re.search('json', headers['Content-Type'], re.IGNORECASE)):
                     request_body = None
                     if body is not None:
                         request_body = json.dumps(body)