def do_regroup_children(self):
<EOL>if len(self) == <NUM_LIT:1>:<EOL><INDENT>child = next(iter(self.children))<EOL>child._regroup(self.group)<EOL><DEDENT>else:<EOL><INDENT>for child, layer in self._children.items():<EOL><INDENT>child._regroup(pyglet.graphics.OrderedGroup(layer, self.group))<EOL><DEDENT><DEDENT>
Put each child widget into a `pyglet.graphics.OrderedGroup` based on 
its layer.