MultiAdapter example in grokcore.component can not work

grokcore.component has this example:

class HelloWorldProvider(grokcore.component.MultiAdapter):
    """Display Hello World!"""
    grokcore.component.adapts(Interface, IBrowserRequest, IBrowserPage)
    grokcore.component.implements(IContentProvider)

    def update(self):
        pass

    def render(self):
        return u'<p>Hello World!</p>'

This code can never work, since unlike grokcore.component.Adapter MultiAdapter does not define a __init__ constructor. As a result an attempt to use this adapter results in an error message:

TypeError: 'object.__new__() takes no parameters'