def prepare_default_result_dict(key, done, nodes):
    """Prepares the default result `dict` using common values returned by any
    operation on the DHT.

    Returns:
        dict: with keys `(k, d, n)` for the key, done and nodes; `n` is a list
            of `dict` with keys `(i, a, x)` for id, address, and expiration.
    """
    d = {
        "k": key,
        "d": done,
    }
    nb = []
    for n in nodes:
        _node = n.getNode()
        nb.append({
            "i": n.getId().toString(),
            "a": _node.getAddr(),
            "x": _node.isExpired()
        })
    d["n"] = nb

    return d