title: Using `self` as a context in a `with` statement
body: <p>I often see code that uses <code>self</code> to manage a context. For example</p>
  
  <pre><code>with self:
      self.x = 4
      self.y = 6
  </code></pre>
  
  <p>What's going on here? What does using <code>self</code> as a context allow?</p>