code: def complete(self, text, line, begin, end):
          
          self.fire_event('precomplete', text, line, begin, end)
          choices = self._complete(text, line, begin, end)
          choices -= self.completion_excludes
          sz = len(choices)
          if sz == 1:
              # XXX: This is pretty bad logic here.  In reality we need much
              # more complicated escape handling and imbalanced quote support.
              return set(shlex.quote(x) for x in choices)
          elif sz > 2:
              # We don't need the sentinel choice to prevent completion
              # when there is already more than 1 choice.
              choices -= {completer.ActionCompleter.sentinel}
          self.fire_event('postcomplete', choices)
          return choices
docs: Get and format completer choices.  Note that all internal calls to
          completer functions must use [frozen]set()s.