def test_help():
    def one(x, y):
        """ Docstring number one """
        return x + y

    def two(x, y):
        """ Docstring number two """
        return x + y

    def three(x, y):
        """ Docstring number three """
        return x + y

    master_doc = 'Doc of the multimethod itself'

    f = Dispatcher('f', doc=master_doc)
    f.add((object, object), one)
    f.add((int, int), two)
    f.add((float, float), three)

    assert f._help(1, 1) == two.__doc__
    assert f._help(1.0, 2.0) == three.__doc__