Remove a relationship from an object.

        Wrapper function for
        `Fedora REST API purgeRelationship <https://wiki.duraspace.org/display/FEDORA34/REST+API#RESTAPI-purgeRelationship>`_

        :param pid: object pid
        :param subject: relationship subject
        :param predicate: relationship predicate
        :param object: relationship object
        :param isLiteral: boolean (default: false)
        :param datatype: optional datatype
        :returns: boolean; indicates whether or not a relationship was
            removed

def purgeRelationship(self, pid, subject, predicate, object, isLiteral=False,
                        datatype=None):
        '''Remove a relationship from an object.

        Wrapper function for
        `Fedora REST API purgeRelationship <https://wiki.duraspace.org/display/FEDORA34/REST+API#RESTAPI-purgeRelationship>`_

        :param pid: object pid
        :param subject: relationship subject
        :param predicate: relationship predicate
        :param object: relationship object
        :param isLiteral: boolean (default: false)
        :param datatype: optional datatype
        :returns: boolean; indicates whether or not a relationship was
            removed
        '''

        http_args = {'subject': subject, 'predicate': predicate,
                     'object': object, 'isLiteral': isLiteral}
        if datatype is not None:
            http_args['datatype'] = datatype

        url = 'objects/%(pid)s/relationships' % {'pid': pid}
        response = self.delete(url, params=http_args)
        # should have a status code of 200;
        # response body text indicates if a relationship was purged or not
        return response.status_code == requests.codes.ok and response.content == b'true'