python3 and RO package and DS9
Question: How to get RO package working in Python 3? I managed to get it to work in
Python 2.7, but when I install it manually as `python3 setup.py install` and
then do `import RO.DS9` I get this:

    
    
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/usr/local/lib/python3.4/dist-packages/RO-3.6.9-py3.4.egg/RO/DS9.py", line 160, in <module>
        import RO.OS
      File "/usr/local/lib/python3.4/dist-packages/RO-3.6.9-py3.4.egg/RO/OS/__init__.py", line 7, in <module>
        from .OSUtil import *
      File "/usr/local/lib/python3.4/dist-packages/RO-3.6.9-py3.4.egg/RO/OS/OSUtil.py", line 31, in <module>
        import RO.SeqUtil
      File "/usr/local/lib/python3.4/dist-packages/RO-3.6.9-py3.4.egg/RO/SeqUtil.py", line 33, in <module>
        import UserString
    ImportError: No module named 'UserString'
    >>> exit()
    


Answer: In Python 3, [`UserString` is part of the `collections`
module](https://docs.python.org/3/library/collections.html?highlight=userstring#collections.UserString).

As you can see on [the RO page](https://pypi.python.org/pypi/RO), this library
does only support Python 2.6 and 2.7.

