How to use the pydoctor.zopeinterface.ZopeInterfaceASTBuilder function in pydoctor

class TwistedFunction(zopeinterface.ZopeInterfaceFunction):

    def docsources(self):

        if self.decorators:
            getDeprecated(self, list(self.decorators))

        for x in super(TwistedFunction, self).docsources():
            yield x



class TwistedASTBuilder(zopeinterface.ZopeInterfaceASTBuilder):
    # Vistor is not a typo...
    ModuleVistor = TwistedModuleVisitor



class TwistedSystem(zopeinterface.ZopeInterfaceSystem):
    """
    A PyDoctor "system" used to generate the docs.
    """
    defaultBuilder = TwistedASTBuilder
    Function = TwistedFunction

    def __init__(self, options=None):
        super(TwistedSystem, self).__init__(options=options)
        # Use custom SphinxInventory so that we can resolve valid L{} markup
        # for which the Sphinx inventory is not published or broken.