code: def make_vertical_box(cls, children, layout=Layout(), duplicates=False):
          "Make a vertical box with `children` and `layout`."
          if not duplicates: return widgets.VBox(children, layout=layout)
          else: return widgets.VBox([children[0], children[2]], layout=layoutf make_vertical_box(cls, children, layout=Layout(), duplicates=False):
          "Make a vertical box with `children` and `layout`."
          if not duplicates: return widgets.VBox(children, layout=layout)
          else: return widgets.VBox([children[0], children[2]], layout=layout)
docs: Make a vertical box with `children` and `layout`.