gistfile1.txt

$ python test_context.py 
CONTEXT: start
USER: got resource
CONTEXT: done
Traceback (most recent call last):
  File "test_context.py", line 32, in <module>
    for i in user():
  File "test_context.py", line 27, in user
    for item in resource:
TypeError: iter() returned non-iterator of type 'MyIterator'

test_context.py

# A simple test that demonstrates my problem

from contextlib import contextmanager

class MyIterator(object):
    def __init__(self):
        self.list = [1,2,3,4,5,6,7,8,9,10]

    def __iter__(self):
        return self

    def __next__(self):
        item = self.list[0]
        print "ITER: yielding %s" % str(item)
        self.list = self.list[1:]
        return item

@contextmanager
def taker():
    print "CONTEXT: start"
    try:
        yield MyIterator()
    finally:
        print "CONTEXT: done"

def user():
    with taker() as resource:
        print "USER: got resource"
        for item in resource:
            print "USER: yielding %s" % str(item)
            yield item


for i in user():
    print "GOT: %s" % str(i)