+1 Array

/*

Given an array of integers of any length, return an array that has 1 added to the value represented by the array.

If the array is invalid (empty, or contains negative integers or integers with more than 1 digit), return nil (or your language's equivalent).

Examples

Valid arrays

[4, 3, 2, 5] would return [4, 3, 2, 6] (4325 + 1 = 4326)
[1, 2, 3, 9] would return [1, 2, 4, 0] (1239 + 1 = 1240)
[9, 9, 9, 9] would return [1, 0, 0, 0, 0] (9999 + 1 = 10000)
[0, 1, 3, 7] would return [0, 1, 3, 8] (0137 + 1 = 0138)
Invalid arrays

[] is invalid because it is empty
[1, -9] is invalid because -9 is not a non-negative integer
[1, 2, 33] is invalid because 33 is not a single-digit integer


*/



def up_array(arr):
    if not arr or not all(isinstance(e, int) and 0 <= e <= 9 for e in arr): return
    ar = int(''.join(map(str,arr))) + 1
    return [int(d) for d in str(ar).zfill(len(arr))]