class Solution:    # @return a string    def longestCommonPrefix(self, strs):        num_items=len(strs)        if num_items<1:            return ""        prefix=strs[0]        for i in strs[1:num_items]:            if len(prefix)>len(i):                prefix=prefix[0:len(i)]            min_len=min(len(i),len(prefix))            for j in range(min_len):                if prefix[j]!=i[j]:                    prefix=prefix[0:j]                    break        return prefixif __name__ == ‘__main__‘:    s=Solution()    #strs=["abd","abcd","abcf","abchrg"]    strs=["flower","flow","flight"]    print(s.longestCommonPrefix(strs))