Make gzipped tarball from a source directory

    :param src_dir: source directory
    :raises TypeError: if src_dir is not str

def make_tarball(src_dir):
    """
    Make gzipped tarball from a source directory

    :param src_dir: source directory
    :raises TypeError: if src_dir is not str
    """
    if type(src_dir) != str:
        raise TypeError('src_dir must be str')
    output_file = src_dir + ".tar.gz"
    log.msg("Wrapping tarball '{out}' ...".format(out=output_file))
    if not _dry_run:
        with tarfile.open(output_file, "w:gz") as tar:
            tar.add(src_dir, arcname=os.path.basename(src_dir))
    return output_file