### Question:
ArgumentTypeRegistry { @SuppressWarnings("unchecked") public static void deregisterCollectionArgumentType( Class<? extends Collection> collectionClass) { if (collectionClass == null) { throw new NullPointerException("collectionClass"); } collectionArgTypeMap.remove(collectionClass); }  static ArgumentType<T> getArgumentType(PropertyDesc propertyDesc); static void registerArgumentType(Class<?> clazz,
            Class<? extends ArgumentType<?>> argumentTypeClass); static void deregisterArgumentType(Class<?> clazz); @SuppressWarnings("unchecked") static void registerCollectionArgumentType(
            Class<? extends Collection> collectionClass,
            Class<? extends CollectionType> argumentTypeClass); @SuppressWarnings("unchecked") static void deregisterCollectionArgumentType(
            Class<? extends Collection> collectionClass);  }### Answer:
@Test public void testDeregisterCollectionArgumentType() throws Exception { ArgumentTypeRegistry.deregisterCollectionArgumentType(List.class); ArgumentType<List<String>> argumentType = ArgumentTypeRegistry .getCollectionArgumentType(List.class, String.class); assertNull(argumentType); }