update python samples

Author: wing328

samples/openapi3/client/petstore/python-experimental/petstore_api/api/fake_api.py

@@ -614,6 +614,7 @@ def __get_array_of_enums(
 
             This method makes a synchronous HTTP request by default. To make an
             asynchronous HTTP request, please pass async_req=True
+
             >>> thread = api.get_array_of_enums(async_req=True)
             >>> result = thread.get()