docstr: Predict the probability of actions
  
  Args:
      obs (paddle tensor): shape of (obs_dim,)
  
  Returns:
      prob (paddle tensor): shape of (action_dim,)
code: def predict(self, obs):
      """Predict the probability of actions
  
      Args:
          obs (paddle tensor): shape of (obs_dim,)
  
      Returns:
          prob (paddle tensor): shape of (action_dim,)
      """
      prob = self.model(obs)
      return prob
  
file_path: PARL/parl/algorithms/paddle/policy_gradient.py
imports: import parl
  import paddle
  from paddle.distribution import Categorical
  from parl.utils.utils import check_model_method
label_desc: Use image node_id 2 for calling the PolicyGradient obj's underlying member method code with example usage: obj.predict(obs) and returns: prob