incomplete final line found warning

Hi,

I saved the following as a UTF-8 encoded file named amberutil.r

as.factor.loop <- function(df, cols){

	if (!is.null(df) && !is.null(cols) && length(cols) > 0)
	{
		for(col in cols)
   {
			df[[col]] <- as.factor(df[[col]])
		}
	}
 df
}

And got this warning message,

source('D:/ambertuil.r')

Warning message:
In readLines(file) : incomplete final line found on 'D:/ambertuil.r'

Can you help with this?