Create the logic of temporarily storing excel bak files

mydir ='bak' #The basic logic is divided into two situations, folder presence and absence, sometimes, in order to avoid data pollution inside, delete and rebuild one; if not, just build one normally

if os.path.exists(mydir) == 0 :
    os.mkdir(mydir)
else:
    shutil.rmtree ('bak')
    os.mkdir(mydir)