docs: def check(self, check_url=None):
          """
          Checks whether a server is running.
  
          :param str check_url:
              URL where to check whether the server is running.
              Default is ``"http://{self.host}:{self.port}"``.
          """
  
          if check_url is not None:
              self.check_url = self._normalize_check_url(check_url)
  
          response = None
          sleeped = 0.0
          t = datetime.now()
  
          while not response:
              try:
                  response = requests.get(self.check_url, verify=False)
              except requests.exceptions.ConnectionError:
                  if sleeped > self.timeout:
                      self._kill()
                      raise LiveAndLetDieError(
                          '{0} server {1} didn\'t start in specified timeout {2} '
                          'seconds!\ncommand: {3}'.format(
                              self.__class__.__name__,
                              self.check_url,
                              self.timeout,
                              ' '.join(self.create_command())
                          )
                      )
                  time.sleep(1)
                  sleeped = _get_total_seconds(datetime.now() - t)
  
          return _get_total_seconds(datetime.now() - t)