'Promote the sticky comment, if any.'

def get_initial_comment_list(self, comment_tree):

    comment_tuples = []
    if self.link.sticky_comment_id:
        root_level_comments = comment_tree.tree.get(None, [])
        sticky_comment_id = self.link.sticky_comment_id
        if (sticky_comment_id in root_level_comments):
            comment_tuples.append(CommentTuple(comment_id=sticky_comment_id, depth=0, parent_id=None, num_children=comment_tree.num_children[sticky_comment_id], child_ids=comment_tree.tree.get(sticky_comment_id, [])))
        else:
            g.log.warning('Non-top-level    sticky    comment    detected    on    link    %r.', self.link)
    return comment_tuples
