code: def commit(self, commands="", confirmed=None, comment=None,
                 at_time=None, synchronize=False, req_format='text'):
          if not commands:
              commands = 'annotate system ""'
          clean_cmds = []
          for cmd in clean_lines(commands):
              clean_cmds.append(cmd)
          self.lock()
          self._session.load_configuration(action='set', config=commands)
          results = ""
          if confirmed:
              results = self._session.commit(confirmed=True,
                                             timeout=str(confirmed),
                                             comment=comment,
                                             synchronize=synchronize)
          else:
              results = self._session.commit(comment=comment, at_time=at_time,
                                             synchronize=synchronize)
          self.unlock()
          if results:
              if req_format == 'xml':
                  return results
              results = ET.fromstring(results.tostring)
              out = ''
              for i in results.iter():
                  if i.tag == 'commit-check-success':
                      out += 'configuration check succeeds\n'
                  elif i.tag == 'commit-success':
                      out += 'commit complete\n'
                  elif i.tag == 'ok':
                      out += 'commit complete\n'
                  elif i.text is not None:
                      if i.text.strip() + '\n' != '\n':
                          out += i.text.strip() + '\n'
                  elif i.text is None:
                      if i.tag + '\n' != '\n':
                          out += i.tag + '\n'
              return out
          return False