def _mav_validator(mav_value):
    """ 
    Value for mav (moving average) keyword may be:
    scalar int greater than 1, or tuple of ints, or list of ints (greater than 1).
    tuple or list limited to length of 7 moving averages (to keep the plot clean).
    """
    if isinstance(mav_value, int) and mav_value > 1:
        return True
    elif not isinstance(mav_value, tuple) and not isinstance(mav_value, list):
        return False
    if not len(mav_value) < 8:
        return False
    for num in mav_value:
        if not isinstance(num, int) and num > 1:
            return False
    return True
