private ListMap<String, String> initSimpleMap() {
        ListMap<String, String> lm = new ListMap<>();
        lm.put(A, "a0");
        lm.put(A, "a1");
        lm.put(B, B0);
        lm.put(B, "b1");
        lm.put("C", "c");
        lm.put("D", "d");
        return lm;
    }
@author <a href="mailto:einarmr@yahoo-inc.com">Einar M R Rosenvinge</a>
vespajlib/src/test/java/com/yahoo/collections/ListMapTestCase.java