/usr/lib/python2.7/dist-packages/xlwt/ExcelFormula.py is in python-xlwt 0.7.5+debian1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/python2.7/dist-packages/xlwt/../../../../share/pyshared/xlwt/ExcelFormula.py