def normalize_series(series, min_max):
    """ Normalizes a series where all values between
        0 and 1. Values can exceed 1 if they exceed the provided
        max in the min_max tuple.

        :param series:      Pandas series to normalize
        :param min_max:     Tuple of minimum and maximum value for
                                normalization.
        
        :return:            Normalized series
    """

    if min_max is None:
        min_max = series.agg(['min', 'max']).values
    
    assert min_max[0] < min_max[1]
    series = (series - min_max[0]) / (min_max[1] - min_max[0])

    return series