How to programmatically collapse a box in shiny dashboard

Question

I'm trying to collapse a box programmatically when an input changes. It seems that I only need to add the class "collapsed-box" to the box, I tried to use the shinyjs function addClass, but I don't know how to do that becuase a box doesn't have an id. Here as simple basic code that can be used to test possible solutions:

library(shinydashboard)

ui <- dashboardPage(
  dashboardHeader(),
  dashboardSidebar(),
  dashboardBody(
      box(collapsible = TRUE,p("Test")),
      actionButton("bt1", "Collapse")
  )
)

server <- function(input, output) {
  observeEvent(input$bt1, {
    # collapse the box
  })
}

shinyApp(ui, server)