def diff(xds_inp_a, xds_inp_b):
    """Compare the parameters in a, b; write out the differences"""
    all_keys = list(sorted(set(xds_inp_a).union(xds_inp_b)))
    for key in all_keys:
        a = xds_inp_a.get(key, '')
        b = xds_inp_b.get(key, '')
        if a == b:
            continue
        print('%s:\n\t%s\n\t%s' % (key, a, b))
