title: python list comprehension with two functions
body: <p>OK, I can do this:    </p>
  
  <pre><code>[i for i in range(100) if i &gt; 10 if i &lt; 50]
  </code></pre>
  
  <p>or I can do this:</p>
  
  <pre><code>[i for i in range(100) if i &gt; 10 and i &lt; 50]
  </code></pre>
  
  <p>BUT, if I try this:</p>
  
  <pre><code>def is_big(number):
      number &gt; 10
  def is_small(number):
      number &lt; 50
  </code></pre>
  
  <p>I get:</p>
  
  <pre><code>[i for I in range(100) if is_big(I) and is_small(I)]
  []
  [i for I in range(100) if is_big(I) if is_small(I)]
  []
  </code></pre>