How to get matrix columns without numpy in Python

mat = [
        [1, 2,3, 5], 
        [4, 6, 7, 8], 
        [9, 10, 11, 12], 
        [13, 14, 15, 16]
    ]


def convertToArr(el):
    return list(el)

cols = list(map(convertToArr, list(zip(*mat))))

print(cols)  # [[1, 4, 9, 13], [2, 6, 10, 14], [3, 7, 11, 15], [5, 8, 12, 16]]