def true_filter(test):  # pylint: disable=unused-argument
    """Simply return True regardless of the input.

    Designed to be used with `get_best_filter` where no filtering is desired;
    intended to have same effect as `IsParticle` function defined in
    dataclasses/private/dataclasses/physics/I3MCTreePhysicsLibrary.cxx

    Parameters
    ----------
    test

    Returns
    -------
    True : bool

    """
    return True