class_docstr: Partially observable variant of the Pendulum gym environment.
  
  https://github.com/Farama-Foundation/Gymnasium/blob/main/gymnasium/envs/
  classic_control/pendulum.py
  
  We delete the angular velocity component of the state, so that it
  can only be solved by a memory enhanced model (policy).
code: def __init__(self, config=None):
      config = config or {}
      g = config.get("g", 10.0)
  
      super().__init__(g=g)
  
      # Fix our observation-space (remove angular velocity component).
      high = np.array([1.0, 1.0], dtype=np.float32)
      self.observation_space = Box(
          low=-high, high=high, dtype=np.float32
      )
  
file_path: ray/python/ray/rllib/examples/env/stateless_pendulum.py
imports: from gymnasium.spaces import Box
  import numpy
  from gymnasium.envs.classic_control import PendulumEnv
label_desc: Use image node_id 1 to create a new StatelessPendulum object from inherited base classes: PendulumEnv with example: obj = StatelessPendulum(config)