def is_outlier(deviation=3):
    """Build a callable taking a `Series` as argument, and returning a new
    `Series` of booleans indicating whether values are in a specific SD range
    or not.
    """
    def func(series):
        mean, std = series.mean(), series.std()

        return ~series.between(
            mean - deviation * std,
            mean + deviation * std
        )
    return func