code: def reason(self, reason):
          
  
          if reason is None:
              raise ValueError("Invalid value for `reason`, must not be `None`")
          if len(reason) > 192:
              raise ValueError("Invalid value for `reason`, length must be less than `192`")
  
          self._reason = reason
docs: Sets the reason of this CreateRefundRequest.
          A description of the reason for the refund.  Default value: `Refund via API`
  
          :param reason: The reason of this CreateRefundRequest.
          :type: str