I've read that one of the key beliefs of Python is that flat nested. However, if I have several variables counting up, what is the alternative to multiple for loops? My code is for counting grid sums and goes as follows: def horizontal(): for x in range(20): for y in range(17): temp = grid[x][y: y + 4] sum = 1 for n in temp: sum += int(n) return sum This seems to me like it is too heavily nested. Firstly, what is considered to many nested loops in Python ( I have certainly seen 2 nested loops before). Secondly, if this is too heavily nested, what is an alternative way to write this code?