title: Error in function, the output must be 30 but not answering where is the problem?
body: <p>Error in function, the output must be 30 but not answering where is the problem?</p>
  <pre><code>def sum(low, high):
      result
      for number in xrange(low, high):
          result = number
      return result
  sum(4,8)
  </code></pre>