레벨2 문제 (못품)
def solution(arr1, arr2):
a1=len(arr1)
a2=len(arr2[0])
answer = [[0]*a2 for _ in range(a1)]
for i in range(a1):
for j in range(a2):
for k in range(len(arr2)):
answer[i][j] += arr1[i][k] * arr2[k][j]
return answer