There is no check if value is not valid (1-9) integer

[mikhail349]

https://github.com/neetcode-gh/leetcode/blob/c49180fc992e6af22b1cb55476f92494be043d04/python/0036-valid-sudoku.py#L2

[mikhail349]

Considering the problem description: must contain the digits 1-9 without repetition. So there is need a check that:

1. value is convertable to Int
2. 1 <= value <= 9