class_docstr: The Model for Mujoco env
  Args:
      obs_space (Box): observation space.
      act_space (Box): action space.
code: def __init__(self, obs_space, act_space):
      super(MujocoModel, self).__init__()
  
      self.fc1 = nn.Linear(obs_space.shape[0], 64)
      self.fc2 = nn.Linear(64, 64)
  
      self.fc_value = nn.Linear(64, 1)
  
      self.fc_policy = nn.Linear(64, np.prod(act_space.shape))
      self.fc_pi_std = paddle.static.create_parameter(
          [1, np.prod(act_space.shape)],
          dtype="float32",
          default_initializer=nn.initializer.Constant(value=0),
      )
  
file_path: PARL/examples/PPO/mujoco_model.py
imports: import parl
  import paddle
  import paddle.nn
  import numpy
label_desc: Use image node_id 1 to create a new MujocoModel object from inherited base classes: parl with example: obj = MujocoModel(obs_space, act_space)