def get_post_by_id(cls, post_id, observer=None):
"""observer代表看到这一篇文章的人。
"""
return Post.get_post_by_id(post_id, observer=observer)
def get_post_by_id(cls, post_id, observer=None):
"""observer代表看到这一篇文章的人。
"""
return Post.get_post_by_id(post_id, observer=observer)
