R Shiny App Ошибка: не числовой c аргумент бинарного оператора

Question

Я написал следующие коды для создания COVID-19 Tracker с использованием пакета R Shiny, который показывает линейные графики случаев и смертей на уровне штата и округа. Но графики не появились. Вместо этого я вижу сообщение об ошибке, в котором говорится, что «non-Numberri c аргумент для двоичного оператора». Любая помощь будет оценена. Спасибо.

ui <- fluidPage(
    sidebarLayout(
        sidebarPanel(
            selectInput(inputId = "state_name",
                        label = "Select State",
                        choices = unique(combined$province_state),
                        selected = "Pennsylvania",
                        multiple = TRUE),
            selectInput(inputId = "scale_type",
                        label = "Select Scale",
                        choices = c("Logarithmic" = "log", "Linear" = "linear"),
                        selected = "Logarithmic"),
            selectInput(inputId = "data_type",
                        label = "Select Data",
                        choices = c("Total Confirmed Cases" = "total_cases", 
                                    "New Cases" = "new_cases", 
                                    "Total Deaths" = "total_deaths", 
                                    "New Deaths" = "new_deaths"),
                        selected = "Total Confirmed Cases"),
            selectInput(inputId = "normalization_option",
                        label = "Select Normalization Option",
                        choices = c("Not Normalized" = FALSE, 
                                    "Normalized by Population" = TRUE),
                        selected = "Not Normalized")),
        mainPanel(
           plotlyOutput("state_graph"),
           plotlyOutput("county_graph")
        )
    )
)

server <- function(input, output, session) {
    reval <- reactive({
        if_else(input$normalization_option == TRUE, 
                input$data_type/population*1000000, 
                input$data_type)
        })

    output$state_graph <- renderPlotly({
        by_state <- combined %>%
            group_by(province_state, date) %>%
            summarise(population = sum(population),
                      total_cases = sum(total_cases),
                      total_deaths = sum(total_deaths)) %>%
            mutate(new_cases = total_cases-lag(total_cases, order_by = date),
                   new_deaths = total_deaths-lag(total_deaths, order_by = date)) %>%
            mutate(over_20 = case_when(
                       total_cases >= 20 ~ 1,
                       TRUE ~ 0)) %>%
            filter(over_20 == 1) %>%
            mutate(days_since_20 = cumsum(over_20)) %>%
            plot_ly(x = ~days_since_20, y = ~reval(), 
                    color = ~province_state, type = "scatter", mode = "lines")
    })

    output$county_graph <- renderPlotly({combined %>%
            filter(province_state == input$state_name) %>%
            group_by(admin2, date) %>%
            mutate(new_cases = total_cases-lag(total_cases, order_by = date),
                   new_deaths = total_deaths-lag(total_deaths, order_by = date)) %>%
            mutate(over_5 = case_when(
                total_cases >= 5 ~ 1,
                TRUE ~ 0)) %>%
            filter(over_5 == 1) %>%
            mutate(days_since_5 = cumsum(over_5)) %>%
            plot_ly(x = ~days_since_5, y = ~reval(), 
                    color = ~province_state, type = "scatter", mode = "lines")
    })
}