code: static TypeMirror getClassArg(Elements elements, Types types, DeclaredType classType) {
      TypeElement classElement = elements.getTypeElement(Class.class.getName());
      TypeParameterElement param = classElement.getTypeParameters().get(0);
      return paramAsMemberOf(types, classType, param);
    }
docs: Returns the {@link TypeMirror} argument found in a given {@link Class} type.