Retrieve original items from a diffed set of nested samples.

def get_orig_items(base):
    """Retrieve original items from a diffed set of nested samples.
    """
    assert "group_orig" in base
    out = []
    for data_diff in base["group_orig"]:
        new = utils.deepish_copy(base)
        new.pop("group_orig")
        out.append(_patch_dict(data_diff, new))
    return out