title: how can I write the lisp function to use the predicate
body: <p>for example, what should I input is here finfirst #'oddp '(1 2 3), and it should find the first odd number return to the list, so what I think I need to do is to write a function just have one argument which is list, but I only know to find the first element in the list, so how can I use the condition in my code</p>
  
  <pre><code> (defun finfirst(list)(cond((null list) nil)
  </code></pre>
  
  <p>if I finish this, then it will told me that I need two argument， I just don't know what should I do for this function, just give me some hint for that</p>