fancy_gym/alr_envs/__init__.py

from gym.envs.registration import register

register(
    id='ALRReacher-v0',
    entry_point='alr_envs.mujoco:ALRReacherEnv',
    max_episode_steps=1000,
)

register(
    id='SimpleReacher-v0',
    entry_point='alr_envs.classic_control:SimpleReacherEnv',
    max_episode_steps=200,
    kwargs={
        "n_links": 3,
    }
)