keep the old function and add funtion to convert gcov file(gcda/gcno) to coberuta.xml 

your code only show how to convert the lcov to cuberuta, I add some code to support how to convert gcov to cuberuta.
            lcov_cobertura.py lcov-file.info -a srcPath:gcdaPath
            lcov_cobertura.py -a srcPath1:gcdaPath1  -a srcPath2:gcdaPath2  

keep old features for your code and add features to convert gcov to coberuta.xml.

(1) copy gcda/gcna to src code folder for every -a option
(2) lcov to lcov info for every srcPath:gcdaPath.
(3) merged the lcov infos to one. 
(4) genhtml the info to html
(5) call your features to do convert.

thanks.

Regards.