Deletes the contents of a query

def delete(self):
        """
        Deletes the contents of a query
        """
        #validate where clause
        partition_key = [x for x in self.model._primary_keys.values()][0]
        if not any([c.field == partition_key.column_name for c in self._where]):
            raise QueryException("The partition key must be defined on delete queries")

        dq = DeleteStatement(
            self.column_family_name,
            where=self._where,
            timestamp=self._timestamp
        )
        self._execute(dq)