def rstest_mw(x, y):
    """rank sum test p value of x > y, Not used because of some bug in mannwhitneyu
  """
    from scipy.stats import ranksums, mannwhitneyu
    st1, p1 = ranksums(x, y)
    try:
        st, p = mannwhitneyu(x, y)
    except:
        return 0.5
    if st1 > 0:
        return p
    else:
        return 1 - p
