Matrix multiplication Write two functions that each multiply two square matrices, one without using numpy's built-in functions, and the other using numpy. The input to the first task is given lists of size size by size elements in each. The second task receives objects of type np.ndarray --- square matrices of the same size. The first function should return a list of lists, and the second should return np.array.

a = [[1,2,3],[1,2,3],[1,2,3]]
b = [[3,3,3],[3,3,3],[3,3,3]]

# without using numpy
def matmul(a, b):
    r = [[0,0,0],
         [0,0,0],
         [0,0,0]]
    for i in range(len(a)):
        for j in range(len(a[0])):
            for k in range(len(a[0])):
                r[i][j] += a[i][k] * b[k][j]
    return r

matmul(a, b)

# using numpy
import numpy as np

def matmul_np(a, b):
    return np.matmul(a, b)

matmul_np(np.array(a), np.array(b))