@Override
    public V get(Object key) {
        return underlying().get(key);
    }
@Test
    public void testDelegationOfGet() {
        new PCollectionsHashMapWrapperDelegationChecker<>()
            .defineMockConfigurationForFunctionInvocation(mock -> mock.get(eq(this)), new Object())
            .defineWrapperFunctionInvocationAndMockReturnValueTransformation(wrapper -> wrapper.get(this), identity())
            .doFunctionDelegationCheck();
    }