from sqlalchemy import *
from sqlalchemy.orm import *
m = MetaData( 'sqlite:///')
ta = Table( 'aaa', m,
    Column( 'x', Integer, primary_key=True),
    Column( 'y', Integer, ),
    )
m.create_all()
class A(object): pass
mapper( A,ta)
s = create_session()
for x in 1,2: s.save( A() )
s.flush()

for s in ta.select().execute():
    print s, type(s)
    print set(s)    #works

q = ta.select().execute()
print set(q)        #fails:
#TypeError: 'NoneType' object is not callable