【python3】leetcode 766. Toeplitz Matrix(easy)

766. Toeplitz Matrix(easy)
A matrix is Toeplitz if every diagonal from top-left to bottom-right has the same element.
Now given an  M x N  matrix, return  True  if and only if the matrix is Toeplitz.  
Example 1:

Input:
matrix = [
  [1,2,3,4],
  [5,1,2,3],
  [9,5,1,2]
]
Output: True
Explanation:
In the above grid, the diagonals are:
"[9]", "[5, 5]", "[1, 1, 1]", "[2, 2, 2]", "[3, 3]", "[4]".
In each diagonal all elements are the same, so the answer is True.

Example 2:

Input:
matrix = [
  [1,2],
  [2,2]
]
Output: False
Explanation:
The diagonal "[1, 2]" has different elements.

class Solution:
    def isToeplitzMatrix(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: bool
        """

        for i in range(1,len(matrix)):
            if matrix[i][1:] != matrix[i-1][:-1]:return False
        return True