ParameterizedClassDesc pcd = pd.getParameterizedClassDesc();
        assertThat(pcd.getRawClass(), is(sameClass(Map.class)));
        assertThat(pcd.getArguments().length, is(2));
        assertThat(pcd.getArguments()[0].getRawClass(), is(sameClass(String.class)));
        assertThat(pcd.getArguments()[1].getRawClass(), is(sameClass(Date.class)));

        pd = bd.getPropertyDesc("hege");
        assertThat(pd.isParameterized(), is(true));

        if (!Collection.class.isAssignableFrom(propertyType) || !isParameterized()) {
            return null;
        }
        final ParameterizedClassDesc pcd = parameterizedClassDesc.getArguments()[0];
        if (pcd == null) {
            return null;
        }
        return pcd.getRawClass();
    }

    @Override
    public Class<?> getKeyClassOfMap() {

        for (int i = 0; i < parameterTypes.length; ++i) {
            parameterDescs[i] = createParameterizedClassDesc(parameterTypes[i], map);
        }
        desc.setArguments(parameterDescs);
        return desc;
    }