title: Attributes initialization/declaration in Python class: where to place them?
body: <p>I was wondering what was the best practice for initializing object attributes in Python, in the body of the class or inside the <code>__init__</code> function?</p>
  
  <p>i.e.</p>
  
  <pre><code>class A(object):
      foo = None
  </code></pre>
  
  <p>vs</p>
  
  <pre><code>class A(object):
     def __init__(self):
         self.foo = None
  </code></pre>