code: def step(self, action_dict):
      if self.state > 0:
          assert (
              action_dict["agent_1"] in self.avail
              and action_dict["agent_2"] in self.avail
          ), "Failed to obey available actions mask!"
      self.state += 1
      rewards = {"agent_1": 1, "agent_2": 0.5}
      obs = {
          "agent_1": {
              "obs": self.observation_space["obs"].sample(),
              "action_mask": self.action_mask,
          },
          "agent_2": {
              "obs": self.observation_space["obs"].sample(),
              "action_mask": self.action_mask,
          },
      }
      terminateds = {"__all__": False}
      truncateds = {"__all__": self.state >= 20}
      return obs, rewards, terminateds, truncateds, {}
  
file_path: ray/rllib_contrib/qmix/tests/test_qmix.py
imports: import unittest
  import numpy
  from gymnasium.spaces import Box, Dict, Discrete, MultiDiscrete, Tuple
  from rllib_qmix.qmix import QMixConfig
  import ray
  from ray.rllib.env.multi_agent_env import MultiAgentEnv
  from ray.tune import register_env
label_desc: Use image node_id 3 for calling the AvailActionsTestEnv obj's underlying member method code with example usage: obj.step(action_dict) and returns: obs,  rewards,  terminateds,  truncateds,  dict