def METHOD_NAME():
    """
    A simple 1-tree sequence with at least 2 inference sites
    (i.e. mutations above a non-sample node), and no mutation times
    """
    ts = msprime.sim_ancestry(10, sequence_length=1000, ploidy=1, random_seed=1)
    ts = msprime.sim_mutations(ts, rate=0.01, random_seed=1)
    ts = assign_individual_ids(ts)
    assert num_nonsample_muts(ts) > 1
    return mark_mutation_times_unknown(ts)