I understand that the callModule() function in R Shiny is outdated syntax, and session$userData should instead be used for inter-module communication. I have tried converting the below example code to using session$userData but keep getting error message like this one:

Error in moduleServer(id, function(input, output, session) { : 
  unused argument (function(input, output, session) {
    observe({
        session$userData$mod1Value <- session$userData$sharedValue() + 10
    })
    output$result1 <- renderText({
        paste("Mod 1 Result = base + 10:", session$userData$mod1Value)
    })
})

How do I replace callModule() with session$userData, in the code shown at the bottom of this post?

Oddly, I tried running the accepted answer in post Shiny: How to pass an input from one module to another? but get a similar error message of:

Warning: Error in moduleServer: unused argument (function(input, output, session) {
    innerModule <- inner_module_server("inner_module")
    output$OOP <- renderPrint({
        innerModule()
    })
})
  50: outer_module_server [#2]
  49: server [#2]
   3: runApp
   2: print.shiny.appobj
   1: <Anonymous>
Error in moduleServer(id, function(input, output, session) { : 
  unused argument (function(input, output, session) {
    innerModule <- inner_module_server("inner_module")
    output$OOP <- renderPrint({
        innerModule()
    })
})

Here is the code I am trying to use session$userData with. Note that I have 2 modules that share data to serve as a template for my modules:

library(shiny)

mod1_ui <- function(id) {
  ns <- NS(id)
  textOutput(ns("result1"))
}

mod1_server <- function(input, output, session, common) {
  output$result1 <- renderText({
    common$mod1Value <- common$sharedValue + 10
    paste("Mod 1 Result = base + 10:", common$mod1Value)
  })
}

mod2_ui <- function(id) {
  ns <- NS(id)
  textOutput(ns("result2"))
}

mod2_server <- function(input, output, session, common) {
  output$result2 <- renderText({
    req(common$mod1Value)
    paste("Mod 2 Result = Mod 1 Result * 2:", common$mod1Value * 2)
  })
}

ui <- fluidPage(
  mainPanel(
    h5(strong("Base value:")),
    sliderInput("svc", "", min = 0, max = 10, value = 0),
    mod1_ui("mod1"),
    mod2_ui("mod2")
  )
)

server <- function(input, output, session) {
  common <- reactiveValues(sharedValue = 0)
  observeEvent(input$svc, { common$sharedValue <- input$svc })
  callModule(mod1_server, "mod1", common = common)
  callModule(mod2_server, "mod2", common = common)
}

shinyApp(ui, server)