def add_child(self, widget):
li_itm = _li(id=self.id + str(self._count))<EOL>li_itm.add_child(widget)<EOL>super(List, self).add_child(li_itm)<EOL>self._items.append((widget, li_itm))<EOL>self._count += <NUM_LIT:1><EOL>
Append a widget to the list.

:param widget: Object inheriting :class:`~.widgets.base.BaseElement`