def renderer(self, context, name):
        """Return a renderer with the given name.
        """

        # The named renderer can be parameterised, i.e. 'renderIt one,two,three'
        args = []
        if name.find(' ') != -1:
            name, args = name.split(None, 1)
            args = [arg.strip() for arg in args.split(',')]

        callable = getattr(self, name % 'render_%s', None)
        if callable is None:
            warnings.warn(
                "Renderer %r missing on %s will result in an exception." % (
                    name, qual(type(self))),
                category=DeprecationWarning,
                stacklevel=1)
            callable = lambda *a, **kw: context.tag[
                "The renderer named '%s' was not found in %r." % (name, self)]

        if args:
            return callable(*args)

        return callable
dataset/ETHPy150Open twisted/nevow/nevow/rend.py/RenderFactory.renderer/swapped operands of `%`