Duplicate a line in emacs

When coding you often have to duplicate a line. This is a little script for your .emacs file to do this:

;; Duplicate it
(defun duplicate()
 "Duplicate it."
 (interactive)
 (let (
       (beg (line-beginning-position))
       (end (line-end-position)))
   (copy-region-as-kill beg end)
   (beginning-of-line)
   (forward-line 1)
   (yank)
   (newline)
   (forward-line -1)))