python如何实现均方误差和均方根误差?

# -*- coding: utf-8 -*-

import math

def get_mse(records_real, records_predict):

    """

    均方误差

    """

    if len(records_real) == len(records_predict):

        return sum([(x - y) ** 2 for x, y in zip(records_real, records_predict)]) / len(records_real)

    else:

        return None

# -*- coding: utf-8 -*-

import math

def get_rmse(records_real, records_predict):

    """

    均方根误差

    """

    mse = get_mse(records_real, records_predict)

    if mse:

        return math.sqrt(mse)

    else:

        return None