title: Combine python f-string with format
body: <p>I want to calculate math operation in a f-string using a variable passed to <code>format</code> method. For example i need something like :</p>
  
  <pre><code>print(f"{{a}} * 3".format(a=2))
  </code></pre>
  
  <p>This code prints:</p>
  
  <pre><code>2 * 3
  </code></pre>
  
  <p>But i want the result that's 6. Also i wont use python <code>eval</code> function to evaluate this string.</p>