def toggleProxyAndRender(node):
   proxy = nuke.root().knob('proxy').value()
   print proxy
   if proxy:
       return

   nuke.root().knob('proxy').setValue(not proxy)
   proxy = nuke.root().knob('proxy').value()
   print proxy

   nuke.executeBackgroundNuke(nuke.EXE_PATH, [node], nuke.FrameRanges([1]), nuke.views(), {'maxThreads':nuke.THREADS, 'maxCache':"4G"})