code: def _normalize_method_name(method):
          
          if not method or not isinstance(method, string_types):
              return method
  
          method = method.lower()
          if method == 'any':
              return SwaggerEditor._X_ANY_METHOD
          else:
              return method
docs: Returns a lower case, normalized version of HTTP Method. It also know how to handle API Gateway specific methods
          like "ANY"
  
          NOTE: Always normalize before using the `method` value passed in as input
  
          :param string method: Name of the HTTP Method
          :return string: Normalized method name