}
        };
    for (Entry<Class<?>, Collection<Object>> entry : distinctValues.asMap().entrySet()) {
      generator.addSampleInstances((Class) entry.getKey(), entry.getValue());
    }
    return generator;
  }

  private static @Nullable Object generateDummyArg(Parameter param, FreshValueGenerator generator)
      throws ParameterNotInstantiableException {