title: Masking part of a string
body: <p>So my question is, I have an assignment that needs to be solved.</p>
  
  <p>I have a simple function:</p>
  
  <pre><code>def multiplicator(x, y):
      var1 = x * y
      return var1
  </code></pre>
  
  <p>I need to use this multiplicator to get this result in another function: </p>
  
  <pre><code>Enter: "5435843398429829"     output: "****************9829"
  </code></pre>
  
  <p>The last 4 digits in the input should not be masked, but the rest should be masked with a "#". </p>