code: def undo_sign_in(entry, session=None):
       # noqa
      if session is None:
          session = Session()
      else:
          session = session
  
      entry_to_delete = (
          session
          .query(Entry)
          .filter(Entry.uuid == entry.uuid)
          .one_or_none()
      )
  
      if entry_to_delete:
          logger.info('Undo sign in: {}'.format(entry_to_delete.user_id))
          logger.debug('Undo sign in: {}'.format(entry_to_delete))
          session.delete(entry_to_delete)
          session.commit()
      else:
          error_message = 'Entry not found: {}'.format(entry)
          logger.error(error_message)
          raise ValueError(error_message)
docs: Delete a signed in entry.
  
      :param entry: `models.Entry` object. The entry to delete.
      :param session: (optional) SQLAlchemy session through which to access the database.