Registers the class in Gym and returns the registered name and the env.

def register_gym_env(class_entry_point, version="v0", kwargs=None):
  """Registers the class in Gym and returns the registered name and the env."""

  split_on_colon = class_entry_point.split(":")
  assert len(split_on_colon) == 2

  class_name = split_on_colon[1]
  # We have to add the version to conform to gym's API.
  env_name = "T2TEnv-{}-{}".format(class_name, version)
  gym.envs.register(id=env_name, entry_point=class_entry_point, kwargs=kwargs)

  tf.logging.info("Entry Point [%s] registered with id [%s]", class_entry_point,
                  env_name)

  return env_name, gym.make(env_name)