need help with solution-checker function

[Gribouillis]

You could use a generator

def indexes():
    r = (0 ,1, 2)
    for i in r:
        yield [(i, j) for j in r]
        yield [(j, i) for j in r]
    yield [(i, i) for i in r]
    yield [(2-i, i) for i in r]
    
def won(grid):
    for r in indexes():
        a, b, c = [grid[i][j] for (i, j) in r]
        if a != '-' and a == b and b == c:
            return True
    return False