code: def is_solved(self):
          
          if self.cube.D == [[Square(self.cube["D"].colour)] * 3] * 3:
              for face in "LFRB":
                  if self.cube.get_face(face)[1:] != [[Square(self.cube[face].colour)] * 3] * 2:
                      return False
              return True
          return False
docs: Check if Cube's F2L is solved.