docs: def reboot_droplet(self, droplet_id):
          """
          This method allows you to reboot a droplet. This is the preferred method
          to use if a server is not responding.
          """
          if not droplet_id:
              raise DOPException('droplet_id is required to reboot a droplet!')
          json = self.request('/droplets/%s/reboot' % droplet_id, method='GET')
          status = json.get('status')
          if status == 'OK':
              return json.get('event_id')
          else:
              message = json.get('message')
              raise DOPException('[%s]: %s' % (status, message))