def getall(self):
        try:
            spec = {'data': {'$exists': 1}}
            fields = {'_id': 0}
            sort = [('tid', 1)]
            cur = self.db.docs.find(spec, fields, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        return [Document(**row) for row in cur]
def _update_dimension(
        self,
        size_diff,
        total_size,
        max_visible_size,
        dimension_request_property):
    if max_visible_size is None:
      is_max_visible_size_unlimited = True
    else:
      is_max_visible_size_unlimited = max_visible_size <= 0