Model model = new Model();
model = model.extend(new Symbol("B11"), false);
model = model.extend(new Symbol("B21"), true);
model = model.extend(new Symbol("P11"), false);
model = model.extend(new Symbol("P12"), false);
model = model.extend(new Symbol("P21"), false);
model = model.extend(new Symbol("P22"), false);
model = model.extend(new Symbol("P31"), true);
Sentence kbs = kb.asSentence();
Assert.assertEquals(true, model.isTrue(kbs));