def is_in_period(month, period):
    """Return which months fall within a specified group of calendar months.

    Parameters
    ----------
    month : int or iterable of ints
        One or a series of calendar month numbers [1..12].
    period : tuple of ints
        Group of calendar month numbers to match against.  These are usually
        consecutive, e.g., [3, 4, 5] for MAM, but they don't have to be.

    Returns
    -------
    return : bool or iterable of bools
        True for month numbers that are in the group.

    """
    try:
        return [m in period for m in month]
    except TypeError:
        return month in period