def get_initial_time_step(env, first_env_id=0):
    """Return the initial time step.
    Args:
        env (AlfEnvironment):
        first_env_id (int): the environment ID for the first sample in this
            batch.
    Returns:
        TimeStep: the init time step with actions as zero tensors.
    """
    time_step = env.current_time_step()
    return time_step._replace(env_id=time_step.env_id + first_env_id)