Add a read-only ``{prop_name}_lst`` property to the element class to
        retrieve a list of child elements matching this type.

def _add_list_getter(self):
        """
        Add a read-only ``{prop_name}_lst`` property to the element class to
        retrieve a list of child elements matching this type.
        """
        prop_name = '%s_lst' % self._prop_name
        property_ = property(self._list_getter, None, None)
        setattr(self._element_cls, prop_name, property_)