def delete(self, tag, ref):
        """Delete from the vgroup the member identified by its tag
        and reference number.

        Args::

          tag    tag of the member to delete
          ref    reference number of the member to delete

        Returns::

          None

        Only the link of the member with the vgroup is deleted.
        The member object is not deleted.

        C library equivalent : Vdeletatagref
                                                  """

        _checkErr('delete', _C.Vdeletetagref(self._id, tag, ref),
                  "error deleting member")