def solve(self):
        """
        Solve the cross.
        """
        result = Formula(path_actions(a_star_search(
            ({f: self.cube[f] for f in "LUFDRB"}, 
             self.cube.select_type("edge") & self.cube.has_colour(self.cube["D"].colour)), 
            self.cross_successors, 
            self.cross_state_value, 
            self.cross_goal, 
            )))
        self.cube(result)
        return result
def solve ( self ) : result = Formula ( path_actions ( a_star_search ( ( { f : self . cube [ f ] for f in "LUFDRB" } , self . cube . select_type ( "edge" ) & self . cube . has_colour ( self . cube [ "D" ] . colour ) ) , self . cross_successors , self . cross_state_value , self . cross_goal , ) ) ) self . cube ( result ) return result
Solve the cross.