def db(database_name='pepe'):
    return psycopg2.connect(database=database_name)

def query_db(query, args=(), one=False):
    cur = db().cursor()
cur.execute(query, args)
r = [dict((cur.description[i][0], value) for i, value in enumerate(row)) for
    row in cur.fetchall()]
cur.connection.close()
return (r[0] if r else None) if one else r
my_query = query_db('select * from majorroadstiger limit %s', (3,))
json_output = json.dumps(my_query)
return SQL table as JSON in python