text: import gym
  
  
  class DummyEnv(gym.Env):
      """Base dummy environment."""
  
      def __init__(self, random, obs_dim=(4, ), action_dim=(2, )):
          self.random = random
          self.state = None
          self._obs_dim = obs_dim
          self._action_dim = action_dim
  
      @property
      def observation_space(self):
          """Return an observation space."""
          raise NotImplementedError
  
      @property
      def action_space(self):
          """Return an action space."""
          raise NotImplementedError
  
      def reset(self):
          """Reset the environment."""
          raise NotImplementedError
  
      def step(self, action):
          """Step the environment."""
          raise NotImplementedError
  