<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def delete_record(self, identifier=None, rtype=None, name=None, content=None, **kwargs):
 """ Delete an existing record. If record does not exist, do nothing. If an identifier is specified, use it, otherwise do a lookup using type, name and content. """

        if not rtype and kwargs.get('type'):
            warnings.warn('Parameter "type" is deprecated, use "rtype" instead.',
                          DeprecationWarning)
            rtype = kwargs.get('type')

        return self._delete_record(identifier=identifier, rtype=rtype, name=name, content=content)