title: python how to change functionality of a method during runtime
body: <p>Wondering if its is possible to change functionalify of a method during runtime e.g </p>
  
  <pre><code>x = obj1 + obj2
  return x+y
  </code></pre>
  
  <p>and you want to add </p>
  
  <pre><code>x = obj1 + obj2
  x+= obj3
  return x+y
  </code></pre>