Mistaken "Error: redfefintion of unused <something>" with alternative imports

When I created (these days rather standard) construct

if sys.version_info[:2] < (2,7):
    import unittest2 as unittest
else:
    import unittest

or

try:
    import unittest2 as unittest
else:
    import unittest

Scribes complain that "Error: redefinition of unused 'unittest' from line 8 on line 10".

--------------------------------------------------------------------------------------------------------------------------------
matej@wycliff: ~$ scribes -i
========================================================
System Info: ('Linux', 'wycliff.ceplovi.cz', '3.7.0-0.31.el7.x86_64.debug', '#1 SMP Mon Jan 14 16:28:26 EST 2013', 'x86_64')
Python Version: 2.7.3 (default, Aug 10 2012, 02:54:27)
[GCC 4.7.1 20120720 (Red Hat 4.7.1-5)]
System Byteorder: little
Python Modules: ('__builtin__', '__main__', '_ast', '_codecs', '_sre', '_symtable', '_warnings', '_weakref', 'errno', 'exceptions', 'gc', 'imp', 'marshal', 'posix', 'pwd', 'signal', 'sys', 'thread', 'zipimport')
========================================================
Scribes Version: 0.4-dev-build1052
Dbus Version: (1, 1, 1)
matej@wycliff: ~$ GTK+ Version: (2, 24, 13)
PyGTK Version: (2, 24, 0)
Psyco Not Installed
========================================================
Running Instance: 1
========================================================
Python Path: /usr/lib/python2.7/site-packages
Plugin Path: /usr/lib64/scribes/GenericPlugins
Data Path: /usr/share/scribes
Executable Path: /usr/bin
========================================================
matej@wycliff: ~$