title: How to define a class attribute with no default value in python
body: <p>I'm a C# developer learning python.</p>
  
  <p>If I want to define a class with certain attributes, but not provide default values for the attributes, how is that done?</p>
  
  <p>For example (this is my best guess of how to do it):</p>
  
  <pre><code>class Spam
      eggs = None
      cheese = None
  </code></pre>
  
  <p>Or, is this legal:</p>
  
  <pre><code>class Spam
      eggs
      cheese
  </code></pre>
  
  <p>Or something else?</p>