How to use the multimethod.multimethod function in multimethod

@multimethod(object, bracket)
def join(seq, sep):
    return sep[0] + join(seq, sep[1] + sep[0]) + sep[1]

@multimethod(paper, rock)
def roshambo(left, right):
    return 'paper covers rock'

@multimethod(tree, object)
def join(seq, sep):
    return join(seq.walk(), sep)

@multimethod(rock, scissors)
def roshambo(left, right):
    return 'rock smashes scissors'

@multimethod(scissors, rock)
@multimethod(rock, scissors)
def roshambo(left, right):
    return 'rock smashes scissors'

def test_get_type():
    method = multimethod(lambda: None)
    assert method.get_type is type

    @method.register
    def _(x: Union[int, type(None)]):
        pass

    assert method.get_type is type

    @method.register
    def _(x: List[int]):
        pass

    assert method.get_type is get_type

@multimethod(object, object)
def roshambo(left, right):
    return 'tie'

@multimethod
def func(arg: bool):
    return bool

  @multimethod(CrossoverOperator, PermutationParameter, *args)
  def apply_to(self, param, *args):
    pass

  @multimethod(DifferenceCrossoverOperator, ConfigurationManipulator, *args)
  def apply_to(self, param, *args):
    pass