def t04_ValueDNE(C, pks, crypto, server):
    """Checks that values not stored at the server return None."""
    score = 0
    alice = C("alice")
    score += alice.download("a") is None
    score += alice.download("b") is None
    score += alice.download("c") is None
    alice.upload("d", "e")
    score += alice.download("e") is None
    score += alice.download("d") == "e"
    return float(score) / 5.0