python - Logging values of variable with kivy.logger -

i want log value of variable using kivy.logger in file.

i added following lines code:

from kivy.logger import logger  logger.debug('ezs-2g:  element: %s', str(element)) 

the following line appears in ide (atom):

[debug             ] [ezs-2g      ]  element: tab_0_obj_sensor 

but log file under c:\users\username.kivy\logs says only:

[debug             ] ezs-2g: %s 

• how write correct value logfile instead of %s?
• how change folder of log files? after packaging (creating "myapp/myapp.exe") want read logs in myapp/logs folder, instead of "c:\users\username.kivy\logs" folder?

os: win7 ; python: 3.4 ; kivy: 1.9

• try 'ezs-2g: element: {}'.format(element)
• change log_dir in config, check logger configuration