#I have the following boxplot
    ToothGrowth%>%ggplot(aes(x=dose, y=len, fill=supp))+
      geom_boxplot()

    #I would like to do a wilcoxon sum rank test on the data and label each comparison between OJ and VC
    stat.test <- ToothGrowth%>%group_by(dose)%>%wilcox_test(len~supp, p.adjust.method = 'BH')%>%
      mutate(y.position = c(29, 35, 39))
    stat.test
    #I try to add the p-values to my boxplots
    ToothGrowth%>%ggplot(aes(x=dose, y=len, fill=supp))+
      geom_boxplot()+
      stat_pvalue_manual(stat.test, label = 'p')

    #However I get the following error:
    # Error in FUN(X[[i]], ...) : object 'supp' not found