====== Drawing components of pdfs in RooFit with pyRoot ======
Instead of doing:
<code python>
sum.plotOn(xframe, RooFit.Components(RooFit.RooArgSet(BG)), RooFit.LineColor(2)) 
</code>
you have to do:
<code python>
argset = RooArgSet(BG)
sum.plotOn(xframe, RooFit.Components(argset), RooFit.LineColor(2))
</code>