title: How to pass arguments to Elisp function?
body: <p>I have this keymap to flush empty lines like this:</p>
  
  <pre><code>(global-set-key (kbd "M-T") (lambda () (interactive) (flush-lines "^[[:space:]]*$")))
  </code></pre>
  
  <p>But this doesn't work over a region. Unrelated lines out of the region are getting merged. But when I select a region and manually try M-x flush-lines RET ^[[:space:]]*$ RET, it works as expected.
  What am I doing wrong ?</p>