Error running slidify("index.Rmd" when running presentation

RStudio IDE
1

Hello, I am getting the error when running the slidify("index.Rmd") function. I was suggested the fix (assignInNamespace("md2html",md2html <- function(md){renderMarkdown(text = md)},ns="slidify") # fix), but it does not work. Please see script below.

library(slidify)

assignInNamespace("md2html",md2html <- function(md){renderMarkdown(text = md)},ns="slidify") # fix

library(rmarkdown)

setwd("~/DataScience/DEVELOPING DATA PRODUCTS")
author("application")

slidify("index.Rmd")