code: @SneakyThrows
     public static <T> T getSingletonFor(Class<?> cz) {
        if (cz == null) {
           return null;
        }
        Method method = getSingletonMethod(cz);
        return method == null ? null : Reflect.on(method, null, true).get();
     }
docs: Gets the singleton instance of a class. Looks for a <code>getInstance</code>, <code>getSingleton</code> or
  <code>createInstance</code> method.
  
  @param <T> the type parameter
  @param cz  The class
  @return The singleton instance or null if the class is not a singleton.