def act(
      self,
      action_spec: entity_lib.ActionSpec = entity_lib.DEFAULT_ACTION_SPEC,
  ) -> str:
    """Always return the first entity name."""
    if action_spec.output_type in entity_lib.FREE_ACTION_TYPES:
      return _ENTITY_NAMES[0]
    elif action_spec.output_type in entity_lib.CHOICE_ACTION_TYPES:
      return action_spec.options[0]
    else:
      raise ValueError(f'Unsupported output type: {action_spec.output_type}')
Always return the first entity name.
concordia/environment/engines/sequential_test.py