LeetCode 422 Valid Word Square

class Solution(object):
    def validWordSquare(self, words):
        """
        :type words: List[str]
        :rtype: bool
        """
        if words is None or len(words) == 0:
            return True
        ls = len(words)
        for i in range(ls):
            for j in range(1, len(words[i])):
                if j >= ls:
                    return False
                if i >= len(words[j]):
                    return False
                if words[i][j] != words[j][i]:
                    return False
        return True

    # def validWordSquare(self, words):
    #     # https://discuss.leetcode.com/topic/63423/1-liner-python/2
    #     # The map(None, ...) transposes the "matrix", filling missing spots with None
    #     return map(None, *words) == map(None, *map(None, *words))