### Question:
ObjectMultistack { public ValueWrapper pop(String keyName) { return getTopAndMaybeRemove(keyName, true); } ObjectMultistack(); void push(String keyName, ValueWrapper valueWrapper); ValueWrapper pop(String keyName); ValueWrapper peek(String keyName); boolean isEmpty(String keyName);  }### Answer:
@Test void testPoppingOfEmptyEntry() { assertThrows(EmptyMultistackEntryException.class, () -> new ObjectMultistack().pop("key")); }