code: def _update_record(self, identifier, rtype=None, name=None, content=None):
          
          if identifier is not None:
              identifier = int(identifier)
              records = self._list_records_internal(identifier=identifier)
          else:
              records = self._list_records_internal(name=name, rtype=rtype)
          LOGGER.debug('Records to update (%d): %s', len(records), records)
          assert records, 'No record found to update'
          success = True
  
          for record in records:
              name = name if name is not None else record['name']
              rtype = rtype if rtype is not None else record['type']
              content = content if content is not None \
                  else record['content']
              success = success and self._create_record_internal(
                  rtype, name, content, record['id'])
          return success
docs: Update a DNS entry identified by identifier or name in the domain zone.
          Any non given argument will leave the current value of the DNS entry.
  
          Args:
            identifier (str): The easyname id of the DNS entry to update.
            [rtype] (str): The DNS rtype (e.g. A, TXT, MX, etc) of the new entry.
            [name] (str): The name of the new DNS entry, e.g the domain for which
                          a MX entry shall be valid.
            [content] (str): The content of the new DNS entry, e.g. the mail
                             server hostname for a MX entry.
  
          Returns:
            bool: True if the record was updated successfully, False otherwise.
  
          Raises:
            AssertionError: When a request returns unexpected or unknown data.