title: Adding The Sum Of Nested List In Scheme
body: <p>I'm using scheme. I'm having no problems in finding the sum of a certain list but I'm quite having trouble in adding the sum when a list has a list in it or AKA Nested List. </p>
  
  <pre><code>(define (my-summation li)
  (if (null? li)
    0
    ((if (list? (car li)) (my-summation (car li))
    (+ (car li) (my-summation (cdr li)))))))
  </code></pre>
  
  <p>This was my input and this was the result of the error. Scheme is my weakness since it involves recursion but I can't seem to find the problem. </p>
  
  <pre><code>&gt; (my-summation '(6 3 -2 5 '(4 2 -3) 4 )) 
  function call: expected a function after the open parenthesis, but received -3
  </code></pre>