code: def create_channel(cls, channel_id, name, importance=IMPORTANCE_DEFAULT,
                         description=""):
          
          app = AndroidApplication.instance()
          if app.api_level >= 26:
              channel = NotificationChannel(channel_id, name, importance)
              channel.setDescription(description)
  
              NotificationChannelManager.get().then(
                  lambda mgr: mgr.createNotificationChannel(channel))
  
              return channel
docs: Before you can deliver the notification on Android 8.0 and higher, 
          you must register your app's notification channel with the system by 
          passing an instance of NotificationChannel 
          to createNotificationChannel().
          
          Parameters
          ----------
          channel_id: String-
              Channel ID
          name: String
              Channel name
          importance: Int
              One of the IMPORTANCE levels
          description: String
              Channel description
              
          Returns
          -------
          channel: NotificationChannel or None
              The channel that was created.