'Yield filepaths and relative filepaths for files in extra_files_path'

def __archive_extra_files_path(self, extra_files_path):

    for (root, dirs, files) in os.walk(extra_files_path):
        for fname in files:
            fpath = os.path.join(root, fname)
            rpath = os.path.relpath(fpath, extra_files_path)
            (yield (fpath, rpath))
