<Expr>$rep_extend() is needed?

[eitsupi]

I was wondering if Series was dispatching extra methods from Expr, so I was comparing it to Python¹ and found this.
It does not exist in Rust/Python and it is not clear to me what it is for.

r-polars/R/expr__expr.R

Lines 3028 to 3042 in 421d2c9

	#' Extend a Series by repeating values
	#'
	#' @param expr Expr or something coercible to an Expr.
	#' @inheritParams Expr_rep
	#' @param upcast If `TRUE` (default), non identical types will be cast to common
	#' supertype if there is any. If `FALSE` or no common super type, having
	#' different types will throw an error.
	#' @return Expr
	#' @examples
	#' pl$select(pl$lit(c(1, 2, 3))$rep_extend(1:3, n = 5))
	Expr_rep_extend = function(expr, n, rechunk = TRUE, upcast = TRUE) {
	other = wrap_e(expr)$rep(n, rechunk = FALSE)
	new = .pr$Expr$append(self, other, upcast)
	if (rechunk) new$rechunk() else new
	}

@sorhawell Please comment if you remember what this was added for and why it is needed.
sorhawell/minipolars@f7a2607

If nothing else I will remove this.

Footnotes

1. Get diff from dir(polars.Series) in Python and ls(polars::.pr$env$RPolarsSeries) in R ↩