def child(self, context, n):
        args = []
        if n.find(' ') != -1:
            name, args = n.split(None, 1)
            args = [arg.strip() for arg in args.split(',')]
        else:
            name = n

        callable = getattr(self, name % 'data_%s', None)
        ## If this page doesn't have an appropriate data_* method...
        if callable is None:
            ## See if our self.original has an IContainer...
            container = inevow.IContainer(self.original, None)
            if container is None:
                raise DataNotFoundError("The data named %r was not found in %r." % (name, self))
            else:
                ## And delegate to it if so.
                return container.child(context, n)

        if args:
            return callable(*args)

        return callable
dataset/ETHPy150Open twisted/nevow/nevow/rend.py/DataFactory.child/swapped operands of `%`