title: Counting instances of a class?
body: <p>I've been cleaning up some code from a module I'm extending and I can't seem to find a way to Pythonify this code:</p>
  
  <pre><code>global_next_id = 1
  
  class Obj:
    def __init__(self):
      global global_next_id
      self.id = global_next_id
  
      global_next_id += 1
  </code></pre>
  
  <p>This code uses a global id to keep track of instances of a class (I need the variable <code>self.id</code> internally as well, and it needs to be a number).</p>
  
  <p>Can anyone suggest a way to Pythonify this code?</p>