docs: def _parse_phone_and_hash(self, phone, phone_hash):
          """
          Helper method to both parse and validate phone and its hash.
          """
          phone = utils.parse_phone(phone) or self._phone
          if not phone:
              raise ValueError(
                  'Please make sure to call send_code_request first.'
              )
  
          phone_hash = phone_hash or self._phone_code_hash.get(phone, None)
          if not phone_hash:
              raise ValueError('You also need to provide a phone_code_hash.')
  
          return phone, phone_hash