code: def pprint_blockers(blockers):
      pprinted = []
      for blocker in sorted(blockers, key=lambda x: tuple(reversed(x))):
          buf = [blocker[0]]
          if len(blocker) > 1:
              buf.append(' (which is blocking ')
              buf.append(', which is blocking '.join(blocker[1:]))
              buf.append(')')
          pprinted.append(''.join(buf))
      return pprinted