def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def main(self):
      UI.OpenDialog(
        VBox(
          Heading("This Is a Heading."),
          Label("This is a Label."),
          PushButton("&OK")
        )
      )
      UI.UserInput()
      UI.CloseDialog()