I am trying to figure out, why the code below throws the error:

```
Error in .local(.Object, ...) : argument "data" is missing, with no default

```

Problem Code:

```
setClass("A", representation(a="numeric"), "VIRTUAL")
setClass("B", representation(b="numeric"), contains="A")

setMethod("initialize", "A", function(.Object, data){
  .Object@a <- data[1]
})

setMethod("initialize", "B", function(.Object, data){
  .Object@b <- data[2]
  callNextMethod()
})

data <- 1:2

new("B", data)

```

Thank you for your help!