Installation on IronPython error

[jenokizm]

how fix it?
output:

Installing 'pystun'
Unhandled exception:
Traceback (most recent call last):
File "C:\Program Files (x86)\IronPython 2.7\Lib\runpy.py", line 182, in run_module
File "C:\Program Files (x86)\IronPython 2.7\Lib\runpy.py", line 111, in get_module_details
File "C:\Program Files (x86)\IronPython 2.7\Lib\site-packages\pip_init.py", line 13, in
File "C:\Program Files (x86)\IronPython 2.7\Lib\site-packages\pip\exceptions.py", line 6, in
File "C:\Program Files (x86)\IronPython 2.7\Lib\site-packages\pip_vendor\six.py", line 701, in
File "C:\Program Files (x86)\IronPython 2.7\Lib\site-packages\pip_vendor\six.py", line 692, in exec_
AttributeError: 'module' object has no attribute '_getframe'
'pystun' failed to install. Exit code: 1