title: Change string value by function
body: <p>I noticed that my code has many statements like this:</p>
  <pre><code>var = &quot;some_string&quot;
  var = some_func(var)
  var = another_func(var)
  print(var)  # outputs &quot;modified_string&quot;
  </code></pre>
  <p>It's really annoying me, it just looks awful (in the opposite of whole Python).
  How to avoid using that and start using it in a way like this:</p>
  <pre><code>var = &quot;some_string&quot;
  modify(var, some_func)
  modify(var, another_func)
  print(var) # outputs &quot;modified_string&quot;
  </code></pre>