mat.py

M = [
[3, 2, 1, 2],
[5, 4, 3, 3],
[7, 3, 6, 4],
]
def sub (M,m,n,x,y):
    import numpy as np
    inp =[[0 for a in range(m)] for s in range(n)] 
    mi=np.array(M)
    for i in range(x,x+m):
        for j in range(y,y+n):
            inp[i-x][j-y]=mi[i,j]
    print (inp)