def check_solution(brett, xIndex, yIndex, solution):
# check if number is already in x row or y column
inX = np.any(brett[xIndex, :] == solution)
inY = np.any(brett[:, yIndex] == solution)
# check if number is in 3x3 box
[xBox, yBox] = SudokuBoard.get_box_index(xIndex, yIndex)
box = brett[xBox[0]:xBox[1] + 1, yBox[0]:yBox[1] + 1]
inBox = np.any(box == np.ones(box.shape) * solution)
if inX or inY or inBox:
return 'incorrect'
else:
return 'correct'
