Created by: Termset

# save the parameters to ./model.ckpt
self.agent.save('./model.ckpt')

I have saved model successfully！ And I want to restore model and render.

 algorithm = IMPALA(
            model,
            sample_batch_steps=config['sample_batch_steps'],
            gamma=config['gamma'],
            vf_loss_coeff=config['vf_loss_coeff'],
            clip_rho_threshold=config['clip_rho_threshold'],
            clip_pg_rho_threshold=config['clip_pg_rho_threshold'])
    agent = MPEAgent(algorithm, obs_shape, act_dim)
    agent.restore('./model.ckpt')

Then the TypeError happend：

    agent.restore('./model.ckpt')
  File "/home/tianqi/anaconda3/lib/python3.6/site-packages/parl/core/fluid/agent.py", line 221, in restore
    filename=filename)
  File "/home/tianqi/anaconda3/lib/python3.6/site-packages/paddle/fluid/io.py", line 798, in load_params
    filename=filename)
  File "/home/tianqi/anaconda3/lib/python3.6/site-packages/paddle/fluid/io.py", line 675, in load_vars
    raise TypeError("program's type should be Program")

TypeError: program's type should be Program```