graphene-django中的自定义参数

Question

如何使用graphene-django在GraphQL中创建自定义参数？

我目前在schema.py中具有此配置：

class Post(DjangoObjectType):
    class Meta:
        model = FeedPost
        interfaces = (graphene.relay.Node,)
        filter_fields = ['id']

class Query(graphene.ObjectType):
         post = graphene.Node.Field(Post)

    def resolve_post(self, info, **kwargs):
        username = kwargs.get('username')
        u = User.objects.get(username=username) 
        users_sources = FeedSource.objects.filter(user=u)
        return FeedPost.objects.filter(feed__feedsource__in=users_sources).annotate(
             source_title=F('feed__feedsource__title')
    )
schema = graphene.Schema(query=Query)

但是我无法弄清楚如何在“ post”上的实际GraphQL查询中将“ username”作为必需参数。