docs: def stop(self, timeout=None):
          """
          Stop OpenVPN process group
          :param timeout: time in seconds to wait for process to stop
          :return:
          """
          if not timeout:
              timeout = self.timeout
          os.killpg(os.getpgid(self.process.pid), signal.SIGTERM)
          self.thread.join(timeout)
          if self.stopped:
              logging.info("OpenVPN stopped")
              if self in OpenVPN.connected_instances:
                  OpenVPN.connected_instances.remove(self)
          else:
              logging.error("Cannot stop OpenVPN!")
              for line in self.notifications.split('\n'):
                  logging.warn("OpenVPN output:\t\t%s" % line)