code: def get_last_nonce(app, key, nonce):
      
      uk = ses.query(um.UserKey).filter(um.UserKey.key==key)\
              .filter(um.UserKey.last_nonce<nonce * 1000).first()
      if not uk:
          return None
      lastnonce = copy.copy(uk.last_nonce)
      # TODO Update DB record in same query as above, if possible
      uk.last_nonce = nonce * 1000
      try:
          ses.commit()
      except Exception as e:
          current_app.logger.exception(e)
          ses.rollback()
          ses.flush()
      return lastnonce
docs: Get the last_nonce used by the given key from the SQLAlchemy database.
      Update the last_nonce to nonce at the same time.
  
      :param str key: the public key the nonce belongs to
      :param int nonce: the last nonce used by this key