Shonky attempt at queens problem

shonky-queens.py

def queens(n, i, a, b, c):
    if i < n:
        for j in range(n):
            if j not in a and i+j not in b and i-j not in c:
                yield from queens(n, i+1, a+[j], b+[i+j], c+[i-j])
    else:
        yield a


def sudoku_ok(solution):
    houses = [int((x-1)/3) for x in solution]
    print(f"  Houses: {houses}")
    # Valid *iff* houses[0:3] are unique, houses[3:6], and houses[6:9]
    ok = len(set(houses[0:3])) == 3
    ok = ok and len(set(houses[3:6])) == 3
    ok = ok and len(set(houses[6:9])) == 3
    return ok


for solution in queens(9, 0, [], [], []):
    if sudoku_ok(solution):
        print(solution)