title: LISP Function that Returns True If Atom Is In List
body: <p>I'm trying to write a function (deep-find) that takes in a list and another argument and returns T if that argument is present in the list. For example, if I called <code>(deep-find '(A B (C D)) 'C)</code> it should return true, but if I called <code>(deep-find '(A B (C D)) 'F)</code> it should return false. Here's the code I have so far, but it returns nil every time:</p>
  
  <pre><code>(defun deep-find (L n)
    (cond
     ((null L) nil)
     ((equal n (car L)) t)
     ((deep-find (cdr L) n))))
  </code></pre>