Hi, Could you tell me how to fix this error?

{
“error”: {
“message”: “Subscription field must return Async Iterable. Received: undefined”
}
}

//schema.graphgl
                type Subscription {
                      course(where: CourseSubscriptionWhereInput): CourseSubscriptionPayload
                    }

//resolver
  const {forwardTo} = require('prisma-binding);
    Subscription: {
        course: forwardTo('db')
      }

Hi, we are gonna need more information to fix this. In the meantime, have you verified that "prisma-binding" is installed ?