R Reference Class issue
===

I am trying to create a simple reference class in R. Here is my code (R beginner):

    MyClass <- setRefClass("MyClass",
                           fields = list(a = "numeric",
                                         b = "numeric"),
                           
                           methods = list(
                             initialize <- function(){
                               print("Initializing")
                               a <<- 1
                               b <<- 2
                             },
                             
                             printValues <- function(){
                               print(a)
                               print(b)
                             }
                             )
                           )
    
    a <- MyClass$new()
    a$printValues()

This produces the following error for the last line, a$printValues:

    Error in envRefInferField(x, what, getClass(class(x)), selfEnv) : 
      "printValues" is not a valid field or method name for reference class “MyClass”

Also, the initializer method is not being called ? 

Can someone point me to where the issue lies here ? Many thanks in advance.