Soma valores das duas diagonais principais.

matrix_sun-diagonal.py

#!/usr/bin/env python3


def diagonal_principal(m):
    ac = 0
    m1 = []
    while ac <= len(m) - 1:
        vet = m[ac]
        vet[ac] += 1
        ac += 1
        m1.append(vet)
    return m1


def diagonal_secundaria(m):
    dec = len(m) - 1
    aux = 0
    m2 = []
    while dec >= 0:
        vet = m[aux]
        vet[dec] += 1
        m2.append(vet)
        dec -= 1
        aux += 1
    return m2


if __name__ == '__main__':
    matrix = [
        [0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0]
    ]
    diagonal_principal(matrix)
    s = diagonal_secundaria(matrix)
    for i in s:
        print(i)