old_contents: ''' PolicyGradientAgentClass.py: Class for a policy gradient agent.
  
  Note: At present, this agent is not implemented.'''
  
  # Python imports.
  import random
  
  # Other imports
  from simple_rl.agents.AgentClass import Agent
  
  class PolicyGradientAgent(Agent):
      ''' Class for a random decision maker. '''
  
      def __init__(self, actions, name=""):
          name = "policy_gradient" if name is "" else name
          Agent.__init__(self, name=name, actions=actions)
  
      def act(self, state, reward):
          '''
          Args:
              state (State)
              reward (float)
  
          Returns:
              (str)
          '''
          pass
  
      def update(self, state, action, reward, next_state):
          '''
          Args:
              state (State)
              action (str)
              reward (float)
              next_state (State)
  
          Summary:
              Perform a state of policy gradient.
          '''
          pass
  
new_contents: ''' PolicyGradientAgentClass.py: Class for a policy gradient agent.
  
  Note: At present, this agent is not implemented.'''
  
  # Python imports.
  import random
  
  # Other imports
  from simple_rl.agents.AgentClass import Agent
  
  class PolicyGradientAgent(Agent):
      ''' Class for a random decision maker. '''
  
      def __init__(self, actions, name=""):
          raise NotImplementedError("Policy Gradient has not yet been implemented.)
  
      def act(self, state, reward):
          '''
          Args:
              state (State)
              reward (float)
  
          Returns:
              (str)
          '''
          pass
  
      def update(self, state, action, reward, next_state):
          '''
          Args:
              state (State)
              action (str)
              reward (float)
              next_state (State)
  
          Summary:
              Perform a state of policy gradient.
          '''
          pass
  
subject: raise NotImplemented for PG