title: SyntaxError: "can't assign to function call"
body: <p>This line:</p>
  <pre><code>invest(initial_amount,top_company(5,year,year+1)) = subsequent_amount
  </code></pre>
  <p>produces an error:</p>
  <pre class="lang-none prettyprint-override"><code>SyntaxError: can't assign to function call
  </code></pre>
  <p>How do I fix this and make use of value of the function call?</p>