'Add an ``_insert_x()`` method to the element class for this child
element.'

def _add_inserter(self):

    def _insert_child(obj, child):
        obj.insert_element_before(child, *self._successors)
        return child
    _insert_child.__doc__ = ('Return    the    passed    ``<%s>``    element    after    inserting    it    as    a    child    in    the    correct    sequence.' % self._nsptagname)
    self._add_to_class(self._insert_method_name, _insert_child)
