Define class variable which refers to a previous class variable in python
<pre><code>class Foo(object):
    a = "/admin'
    b = Foo.a + '/hello'
</code></pre>

<p><code>a</code> refers to a base path. And I want to define the class variable <code>b</code> based on <code>a</code>.
How do I achieve this ?</p>
