add docstrings in multitif.py
add docstrings in multitif.py

zhwa/thunder,mikarubi/thunder,thunder-project/thunder,kcompher/thunder,poolio/thunder,zhwa/thunder,oliverhuangchao/thunder,kcompher/thunder,kunallillaney/thunder,kunallillaney/thunder,broxtronix/thunder,j-friedrich/thunder,oliverhuangchao/thunder,broxtronix/thunder,pearsonlab/thunder,mikarubi/thunder,pearsonlab/thunder,jwittenbach/thunder,poolio/thunder,j-friedrich/thunder