How to use the pony.orm.desc function in pony

def latest_entry():
        # Cache-busting query based on most recently-visible entry
        cb_query = queries.build_query({})
        cb_query = cb_query.order_by(orm.desc(model.Entry.utc_date))
        latest = cb_query.first()
        if latest:
            LOGGER.debug("Most recently-scheduled entry: %s", latest)
            return latest.id
        return None

topics = orm.select(rv for rv in Topic if rv.reply_count == 0).order_by(lambda:
                                                                                    orm.desc(rv.created_at))
        else:

NONE = 2    # none of the criteria are present
    NOT = 2     # synonym for NONE


# Ordering queries for different sort orders
ORDER_BY = {
    'newest': (orm.desc(model.Entry.local_date), orm.desc(model.Entry.id)),
    'oldest': (model.Entry.local_date, model.Entry.id),
    'title': (model.Entry.sort_title, model.Entry.id)
}

REVERSE_ORDER_BY = {
    'newest': (model.Entry.local_date, model.Entry.id),
    'oldest': (orm.desc(model.Entry.local_date), orm.desc(model.Entry.id)),
    'title': (orm.desc(model.Entry.sort_title), orm.desc(model.Entry.id))
}


def where_entry_visible(query, date=None):
    """ Generate a where clause for currently-visible entries

    Arguments:

    date -- The date to generate it relative to (defaults to right now)
    """

    return query.filter(lambda e:
                        e.status == model.PublishStatus.PUBLISHED.value or (
                            e.status == model.PublishStatus.SCHEDULED.value and (
                                e.utc_date <= (date or arrow.utcnow().datetime))
                        ))

from flask import url_for
from flux import app, config, utils

import datetime
import hashlib
import os
import pony.orm as orm
import shutil
import uuid

db = orm.Database(**config.database)
session = orm.db_session
commit = orm.commit
rollback = orm.rollback
select = orm.select
desc = orm.desc


class User(db.Entity):
  _table_ = 'users'

  id = orm.PrimaryKey(int)
  name = orm.Required(str, unique=True)
  passhash = orm.Required(str)
  can_manage = orm.Required(bool)
  can_download_artifacts = orm.Required(bool)
  can_view_buildlogs = orm.Required(bool)
  login_tokens = orm.Set('LoginToken')

  def __init__(self, **kwargs):
    if 'id' not in kwargs:
      kwargs['id'] = (orm.max(x.id for x in User) or 0) + 1

reply = collipa.models.Reply.select(lambda rv: rv.topic_id == self.id).order_by(lambda:
                                                                           orm.desc(rv.created_at)).first()
        return reply

            user_ids = user_ids.order_by(lambda: orm.desc(rv.created_at))

            topics = orm.select(rv for rv in Topic).order_by(lambda: orm.desc(rv.last_reply_date))
        if isinstance(topics, list):

def index(self):
        '''Get all people, ordered by creation date.'''
        all_people = orm.select(p for p in Person).order_by(orm.desc(Person.created))[:]
        data = PersonSerializer(all_people, exclude=('created',)).data
        return jsonify({"people": data})