@tornado.gen.coroutine
    def perform(self, ctx, propname, nod=RootPlaceholder):
        ctx.task.tick()
        
        if nod is RootPlaceholder:
            nod = self.nod

        if nod is None:
            return
        if not isinstance(nod, GenNodeClass):
            val = str(nod)
            if val:
                ctx.accum_append(val)
            return
        yield nod.perform(ctx, propname, self)
varargslist : fpdef varargslist_list COMMA STAR NAME COMMA DOUBLESTAR NAME
dataset/ETHPy150Open erkyrath/tworld/lib/twcommon/gentext.py/GenText.perform--crossover with--dataset/ETHPy150Open nucleic/enaml/enaml/core/parser.py/p_varargslist7