code: @SuppressWarnings("all")
      public static synchronized <T> IExpectationSetters<T> expectPrivate(Object instance, String methodName,
                                                                          Class<?>[] parameterTypes, Object... arguments) throws Exception {
  
          if (arguments == null) {
              arguments = new Object[0];
          }
  
          if (instance == null) {
              throw new IllegalArgumentException("instance cannot be null.");
          } else if (arguments.length != parameterTypes.length) {
              throw new IllegalArgumentException(
                      "The length of the arguments must be equal to the number of parameter types.");
          }
  
          Method foundMethod = Whitebox.getMethod(instance.getClass(), methodName, parameterTypes);
  
          WhiteboxImpl.throwExceptionIfMethodWasNotFound(instance.getClass(), methodName, foundMethod, parameterTypes);
  
          return doExpectPrivate(instance, foundMethod, arguments);
      }
docs: Used to specify expectations on private methods. Use this method to
  handle overloaded methods.