Thanks a lot René for your kind positive input. Your solution actually works!!
I just did two things in Shell Variables: (1) Define variable name 'TM_PYTHON' and its value '/usr/bin/python'. As you said it is assumed and so not necessary. But to be explicit I wrote it. This python version is 2.7.10 (default, Jul 14 2015, 19:46:27). (2) Define variable name 'PYTHONPATH' and its value '$PATH:/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/'. It is crucially important. The version 2.7 is not working here at present.
Best Regards, Riki