Stem broken on python2.5

stem git:(master) : git rev-parse HEAD
bee3c2b53653976a36b16a7cefb6e11bb56e4045
stem git:(master) : python2.5 ./run_tests.py -i
Traceback (most recent call last):
  File "./run_tests.py", line 27, in <module>
    import test.unit.connection.authentication
  File "/Users/sathya/Documents/stem/test/unit/connection/authentication.py", line 14, in <module>
    import stem.connection
  File "/Users/sathya/Documents/stem/stem/connection.py", line 111, in <module>
    import stem.control
  File "/Users/sathya/Documents/stem/stem/control.py", line 139, in <module>
    import io
ImportError: No module named io