message: fix following ego agent
diff: @@ -64,7 +64,7 @@ class BaseViewer(Viewer):
  def _update_world_view_range(self, world, eval_agent_ids=None):
  draw_eval_agent_id = self._get_draw_eval_agent_ids(world, eval_agent_ids)
  - if draw_eval_agent_id:
  + if draw_eval_agent_id != None:
  follow_agent = world.agents[draw_eval_agent_id]
  state = follow_agent.state
  pose = np.zeros(3)
  @@ -211,7 +211,7 @@ class BaseViewer(Viewer):
  if self.draw_route:
  self.drawRoute(agent)
  - self.drawHistory(agent, color)
  + # self.drawHistory(agent, color)
  def drawDrivingCorridor(self, corridor, color=None):
  if color is None:
  