class_docstr: Base class used to display multiple child widgets.
code: def _observe_children(self, change):
      self._reset_selected_index()
      self._reset_titles()
  
imports: from .widget_box import Box
  from .widget import register
  from .widget_core import CoreWidget
  from traitlets import Unicode, Dict, CInt, TraitError, validate, observe
  from .trait_types import TypedTuple
  from itertools import chain, repeat, islice
label_desc: Use image node_id 3 for calling the _SelectionContainer obj's underlying member method code with example usage: obj._observe_children(change) without return types