code: def _merge_defaults(self, data, method_params, defaults):
          
          if defaults:
              optional_args = method_params[-len(defaults):]
              for key, value in zip(optional_args, defaults):
                  if not key in data:
                      data[key] = value
          return data
docs: Helper method for adding default values to the data dictionary.
  
          The `defaults` are the default values inspected from the method that
          will be called. For any values that are not present in the incoming
          data, the default value is added.