def _choice_evaluator(choice_array, choice_condition):
    """
    Determines which rows in `choice_array` meet the given `choice_condition`,
    where `choice_condition` is in the set `{0.0, 1.0}`.

    Parameters
    ----------
    choice_array : 1D ndarray of ints that are either 0 or 1.
    choice_condition : int in `{0, 1}`.

    Returns
    -------
    bool_mask : 1D ndarray of bools.
        Equal to `choice_array == choice_condition`
    """
    if choice_condition in [0.0, 1.0]:
        return choice_array == choice_condition
    else:
        msg = "choice_condition MUST be either a 0 or a 1"
        raise ValueError(msg)