def _make_alg_experience(experience, name):
    """Given an experience, extracts the ``rollout_info`` field for an
    algorithm.
    """
    if experience.rollout_info == ():
        rollout_info = ()
    else:
        rollout_info = getattr(experience.rollout_info, name)
    return experience._replace(
        rollout_info=rollout_info,
        rollout_info_field=experience.rollout_info_field + '.' + name)