code: def assign_prompter(self, prompter):
          
          if is_string(prompter):
              if prompter not in prompters:
                  eprint("Error: '{}' is not a core prompter".format(prompter))
                  sys.exit()
              self.prompter = prompters[prompter]
          else:
              self.prompter = prompter
docs: If you want to change the core prompters registry, you can
          override this method in a Question subclass.