Unpacking it is. [e.g.](http://www.pythontutor.com/visualize.html#code=f%20%3D%20%5B1,%202%5D%0Ax,%20y%20%3D%20f&cumulative=false&curInstr=2&heapPrimitives=nevernest&mode=display&origin=opt-frontend.js&py=3&rawInputLstJSON=%5B%5D&textReferences=false)
– user2165Oct 28 '19 at 13:21