title: point from a list into a dicitonary variable
body: <p>Assume you have a list</p>
  
  <pre><code>a = [3,4,1]
  </code></pre>
  
  <p>I want with this information to point to the dictionary:</p>
  
  <pre><code>b[3][4][1]
  </code></pre>
  
  <p>Now, what I need is a routine. After I see the value, to read and write a value inside b's position. </p>
  
  <p>I don't like to copy the variable. I want to change variable b's content directly. </p>