Hi Tom:

Thanks for the test case. I had to make a change to get it to work 
under python2. The code now reads:

 ...
        expected_names = ['context', 'user_realnames', 'x']
        got_names = pe._f_varnames
        try:
            self.assertItemsEqual(expected_names, got_names)
        except AttributeError:
            self.assertCountEqual(expected_names, got_names)

however I expected this to pass when run as:

   python2 ./run_tests.py test/test_pythonexpr.py

without any patches to the roundup code since this problem doesn't 
happen under python2. But it fails with:

...      try:
>           self.assertItemsEqual(expected_names, got_names)
E           AssertionError: Element counts were not equal:
E           First has 1, Second has 0:  'x'
E           First has 0, Second has 1:  'assignedto'
E           First has 0, Second has 1:  'realname'

It also fails under python 3 with:

            self.assertItemsEqual(expected_names, got_names)
        except AttributeError:
>           self.assertCountEqual(expected_names, got_names)
E           AssertionError: Element counts were not equal:
E           First has 1, Second has 0:  'user_realnames'
E           First has 1, Second has 0:  'x'
E           First has 0, Second has 1:  'assignedto'

Does the indicate we have had issues under python2 and just never 
noticed?

With your patch to PythonExpr.py both test cases pass.

If you can shed a little light on the unexpected python 2 failure
without the patch I would appreciate it.

-- rouilj