# -*- coding: utf-8 -*-
import re


def pascal_to_snake(camel_case: str):
    """大驼峰（帕斯卡）转蛇形"""
    snake_case = re.sub(r"(?P<key>[A-Z])", r"_\g<key>", camel_case)
    return snake_case.lower().strip('_')


def snake_to_pascal(snake_case: str):
    """蛇形转大驼峰（帕斯卡）"""
    words = snake_case.split('_')
    return ''.join(word.title() for word in words)


if __name__ == '__main__':
    print(pascal_to_snake('AHelloJello'))
    print(snake_to_pascal('a_hello_jello'))