code: def step(self, action):
      action = np.expand_dims(action, 0)
      assert self.action_space.contains(action), "%r (%s) invalid" % (
          action,
          type(action),
      )
      # Cast action to float to strip np trappings
      force = self.force_mag * float(action)
      self.state = self.stepPhysics(force)
      x, x_dot, theta, theta_dot = self.state
      done = (
          x < -self.x_threshold
          or x > self.x_threshold
          or theta < -self.theta_threshold_radians
          or theta > self.theta_threshold_radians
      )
      done = bool(done)
  
      if not done:
          reward = 1.0
      elif self.steps_beyond_done is None:
          # Pole just fell!
          self.steps_beyond_done = 0
          reward = 1.0
      else:
          if self.steps_beyond_done == 0:
              logger.warn(
                  """
  You are calling 'step()' even though this environment has already returned
  done = True. You should always call 'reset()' once you receive 'done = True'
  Any further steps are undefined behavior.
                  """
              )
          self.steps_beyond_done += 1
          reward = 0.0
  
      return np.array(self.state), reward, done, {}
  
file_path: PARL/examples/tutorials/parl2_dygraph/lesson5/ddpg/env.py
imports: import math
  import gym
  from gym import spaces, logger
  from gym.utils import seeding
  import numpy
label_desc: Use image node_id 4 for calling the ContinuousCartPoleEnv obj's underlying member method code with example usage: obj.step(action) and returns: np,  reward,  done,  dict