title: How do I access the base_pixel_scale attribute of a HasTraits/Chaco/Enable/Kiva Python GUI application?
body: <p>How do I navigate the class hierarchy of a <code>Traits/UI</code>/<code>Chaco</code>/<code>Enable</code>/<code>Kiva</code> Python GUI application, so as to access the <code>base_pixel_scale</code> attribute of the underlying <code>window</code> element?</p>
  <p>That is, what do I replace &quot;?&quot; below with?</p>
  <pre class="lang-py prettyprint-override"><code>class Foo(HasTraits):
      def bar(self):
          print(f&quot;Base Pixel Scale: {self.?.window.base_pixel_scale}&quot;)
  </code></pre>