def get_docs_to_commit(self):
        try:
            spec = {'synced': False}
            fields = {'_id': 0}
            cur = self.db.docs.find(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        return list(cur)
def pop(self, key, default=None):
        value = self._collection.pop(key, default)
        return self._to_python(value)