psycopg2 returns tuples of string

Today I was fiddling with PostgreSQL (v8.3, if anyone is interested) database from Python using famous psycopg2, but suddenly got stuck in unexpected place. Had switched to bpython shell I saw the following:

>>> cur.execute('''SELECT (parent, level) FROM "MsgElems" WHERE msg_id=1;''')

>>> cur.fetchone()

('(0,1)',)

SELECT returned tuple of string, one string. Now that’s what I call unexpected… I didn’t find anything neither in Python DBAPI PEP nor psycopg docs, but after some time a bright idea came:

>>> cur.execute('''SELECT parent, level FROM "MsgElems" WHERE msg_id=1;''')

>>> cur.fetchone()

(0, 1)

Watch out. Meanwhile I’ll try to find out, what triggers such weird behaviour, and if it is weird at all.