求解最长公共前缀问题使用横向扫描的思路，代码检查合理，求强者帮助

Question

def longestCommonPrefix(self, strs: List[str]) -> str:
    prefix = strs[0]
    for i in range(1,len(strs)):
        prefix =self.scan(prefix,strs[i])
    return prefix
def scan(self,str1,str2):
    len1=len(str1)
    len2=len(str2)
    minlen = min(len1,len2)
    for i in range(minlen):
        if str1[i]!=str2[i]:
            return str1[:i]