def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def log_stream(self, logger_name, level_name, format_str):
        """ Attaches a log handler to the specified logger and sends emitted logs 
            back as stream. 
        """
        if logger_name != "" and logger_name not in self.available_loggers():
            raise ValueError("logger {0} is not available".format(logger_name))

        level_name_upper = level_name.upper() if level_name else "NOTSET"
        try:
            level = getattr(logging, level_name_upper)
        except AttributeError, e:
            raise AttributeError("log level {0} is not available".format(level_name_upper))