[mezzode]

`if-else` for this will get messy quickly the more layers down you want to go.

  if a is not None and a.b is not None:
      c = a.b.c
  else:
      c = None

vs

  c = a?.b?.c

The safe navigation operator is useful enough that beginners ought to be introduced to them anyway. I will admit that adding `??` may be too much though, we could easily just use an `or` (although the PEP does have some justifications for adding it).