(defun count-blank-lines (&optional arg)
  (interactive "p")
  (let ((count 0)
    (reg "^$")
    (end (point-max)))
    (while (and (null (= (point) end))
        (re-search-forward reg end t))
      (cl-incf count)
      (forward-line))
    (if arg
    (message "%d blank lines found" count)
      count)))