code: def format_answers(self, fmt='obj'):
          
          fmts = ('obj', 'array', 'plain')
          if fmt not in fmts:
              eprint("Error: '{}' not in {}".format(fmt, fmts))
              return
  
          def stringify(val):
              if type(val) in (list, tuple):
                  return ', '.join(str(e) for e in val)
              return val
  
          if fmt == 'obj':
              return json.dumps(self.answers)
          elif fmt == 'array':
              answers = [[k, v] for k, v in self.answers.items()]
              return json.dumps(answers)
          elif fmt == 'plain':
              answers = '\n'.join('{}: {}'.format(k, stringify(v)) for k, v in self.answers.items())
              return answers
docs: Formats answers depending on `fmt`.