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 is_sql_dirty(sql):
    # This should not happen as using bytes in Python 3 is against db protocol,
    # but some people will pass it anyway
    if isinstance(sql, bytes):
        sql = sql.decode()
    # NOTE: not using regex here for speed
    sql = sql.lower()
    for action in ('update', 'insert', 'delete'):
        p = sql.find(action)
        if p == -1:
            continue
        start, end = p - 1, p + len(action)
        if (start < 0 or sql[start] not in CHARS) and (end >= len(sql) or sql[end] not in CHARS):
            return True
    else:
        return False