```
class Solution(object):
def imageSmoother(self, M):
"""
:type M: List[List[int]]
:rtype: List[List[int]]
"""
res = [[1] * len(M[0]) for _ in range(len(M))]
for row in range(len(M)):
for col in range(len(M[0])):
d = [-1, 0, 1]
vad_m = [M[row + r][col + c] \
for r in d \
for c in d \
if 0 <= row + r <= len(M) - 1 and \
0 <= col + c <= len(M[0]) - 1]
avg = int(sum(vad_m) / len(vad_m))
res[row][col] = int(avg)
return res
```

BTW, be careful with the initialization of `list of list`

in python!

Eg.

If:

`a = [[0] * 3] * 3`

when assignment:

`a[0][0] = 1`

we obtain

```
a:
[[1, 0, 0],
[1, 0, 0],
[1, 0, 0]]
```

instead of

```
a:
[[1, 0, 0],
[0, 0, 0],
[0, 0, 0]]
```