code: def recognise(self):
          
          if not isinstance(self.cube, Cube):
              raise ValueError("Use Solver.feed(cube) to feed the cube to solver.")
          result = ""
          for face in "LFRB":
              for square in self.cube.get_face(face)[0]:
                  result += str(int(square == self.cube["U"]["U"]))
          if result not in algo_dict:
              raise ValueError("Invalid Cube, probably didn't solve F2L, or wrong input value.\nUse Solver.feed(cube) to reset the cube.")
          self.case = result
          return result
docs: Recognise which is Cube's OLL case.