In R could not find function "%

I've found an R script online that I cannot run because it uses %<-%.

could not find function "%<-%"

I've tried to open libraries that have the pipe function (i.e., %>% ) since the script is using it too, including dplyr and magrittr. I've also tried to search online with no luck.

This is an example of how it is being used in the script:

tokenize_fun = function(dataset) {
  c(indices, target, segments) %<-% list(list(),list(),list())
  for ( i in 1:nrow(dataset)) {
    c(indices_tok, segments_tok) %<-% tokenizer$encode(dataset[[DATA_COLUMN]][i], 
                                                       max_len=seq_length)
    indices = indices %>% append(list(as.matrix(indices_tok)))
    target = target %>% append(dataset[[LABEL_COLUMN]][i])
    segments = segments %>% append(list(as.matrix(segments_tok)))
  }
  return(list(indices,segments, target))
}