如何用“*”替换以下出现的第一个字母？

Question

我被困在这个问题上，我不知道该怎么做。

# returns a string that changes all occurrences of its first char have been changed to '*'


def fix_start(str):
    results = []
    str.startswith(str[1])
    results = 

例如：给定 string = 'bubble' 它应该返回：bu**le

Answer 1

def fix_start(s):
    return s[0]+ s[1:].replace(s[0],'*')