pyscopg2 recursive query results differ from psql - Mailing list psycopg

I am trying to work with PostgreSQL CTE to deal with a hierarchical
question.  I have a group who's members are people or other groups.
Groups are identified by negative number and real people with a positive
number. The question, who are all the members of the group?

    CREATE TABLE userroles (
        rid    INTEGER rid, -- Role ID
        ruid   INTEGER,     -- Role or user ID
        PRIMARY KEY(ruid, rid)
    );

Role -1 has users 1, 2, 3, 4 and role -2
Role -2 has users 5, 6 and role -3
Role -3 has users 8 and 9

To find all the users of role -1 I can use the following in PSQL

    WITH RECURSIVE member_role_uids(rid, ruid) AS (
      SELECT rid, ruid
      FROM rr_userroles
      WHERE rid = -1
    UNION
      SELECT rr.rid, rr.ruid
      FROM rr_userroles AS rr, member_role_uids AS mru
      WHERE rr.rid = mru.ruid
    )
    SELECT * from member_role_uids;

I get the wonderful output of

     rid | ruid
    -----+------
      -1 |    1
      -1 |    2
      -1 |    3
      -1 |    4
      -1 |   -2
      -2 |    5
      -2 |    6
      -2 |   -3
      -3 |    8
      -3 |    9
    (10 rows)

This is good enough for me.  However in psycopg2 I get None returned
from cursor.execute(query)

Goggling about didn't give me any leads, or I'm using the wrong terms.
I'm hoping someone else has run across this or can point me in the right
direction.
psql 9.1.7
psycopg2 2.4.5 (dt dec mx pq3 ext)