Manipulate regions

A useful code snippet to manipulate regions.

(defun my/org-convert-region-quote ()
  "Converts selection in a QUOTE block"
  (interactive)
  (progn (insert "#+END_QUOTE\n")
         (exchange-point-and-mark)
         (insert "#+BEGIN_QUOTE\n")))

Knowing about point and mark is useful to understand the code. One defect of this code is that it doesn't work if you select a region starting from the end.