问创建一个空的Plotly图形，标题不显示标题，但在R闪亮应用程序中完全空白

EN

  observeEvent(input$selected_city, {
    if(input$selected_city %in% scenario$place)
    {
  output$Scenario <-
    renderPlotly({
      legendtitle <- list(text=paste0("<b>City: ",test_sc()$place),font=list(size=11, 
      test_sc <- plot_ly(test_sc(), width=700,height=550) 
      test_sc <- add_lines(test_sc,x=~date,y=~incc,color=I('blue'),name='actual',showlegend=F)
    })
  }
  else{
    output$Scenario <-
      renderPlotly({
          p <- plotly_empty(test_sc(),type = "scatter", mode = "markers") %>%
          layout(title = list(
              text = 'Sorry! The graph is not available for this city!',
              yref = "paper",
              xref= "paper",
              x = 0.5,
              y = 0.5
            )
          )
          return(p)
          })
  }