Thanks for response but this don't works.
I see the log file with "ls -l" that the file is 0KB until the program finish and then is full of all information.
It looks like python is buffering output so there is no external way to view the results until python flushes its output buffer. Normally this will happen when the buffer fills and when python closes the output file. If you have permission to change the python source file (example.py), consider adding flush() calls to appropriate spots in the code so tail will be able to see data written to the file after significant updates are written.