update xrange() to range() as Python 2 has been deprecate, more info:
1.  Python 2 has been no longer supported officially since January 1, 2020.  Check  https://www.python.org/doc/sunset-python-2/
2.  xrange() was renamed to range() in Python 3. Check  https://stackoverflow.com/questions/17192158/nameerror-global-name-xrange-is-not-defined-in-python-3/17192181#17192181

update xrange() to range()

Update py_fourier_transform.markdown

update xrange() to range()

* [ts][summary.py] Extend `-o` to support tabs separated output.

* [ts][summary.py] Improve TABS sepatated output.

There is no need to print TAB at the beginning and at the end of each
row in the table.

Cosmetic change: using python list comprehension instead of for loop
to process a single row.

https://github.com/opencv/opencv/issues/19299

* Remove sentences about SIFT patent and code location

* Add note about patent in opencv-specific section

Argument `minLinLength` -> `minLineLength`

Fix cvSaveImage( ) function bug

* fix cvSaveImage crash

* replace emplace_back with {}, no C++11 required

* fix MacOSX build with vector's push_back

original commit: 3ed376d1

- don't switch between Python versions in the middle of the build