Add a ``_remove_x()`` method to the element class for this child
        element.

def _add_remover(self):
        """
        Add a ``_remove_x()`` method to the element class for this child
        element.
        """
        def _remove_child(obj):
            obj.remove_all(self._nsptagname)
        _remove_child.__doc__ = (
            'Remove all ``<%s>`` child elements.'
        ) % self._nsptagname
        self._add_to_class(self._remove_method_name, _remove_child)