def METHOD_NAME(file1: str, file2: str) -> None:
    """
    Assert that two files have the same group owner.
    :param str file1: first file path to compare
    :param str file2: second file path to compare
    """
    # On Windows there is no group, so this assertion does nothing on this platform
    if POSIX_MODE:
        group_owner_file1 = grp.getgrgid(os.stat(file1).st_gid)[0]
        group_owner_file2 = grp.getgrgid(os.stat(file2).st_gid)[0]
        assert group_owner_file1 == group_owner_file2