title: Convert UPPERCASE string to sentence case in Python
body: <p>How does one convert an uppercase string to proper sentence-case? Example string:</p>
  
  <pre><code>"OPERATOR FAIL TO PROPERLY REMOVE SOLID WASTE"
  </code></pre>
  
  <p>Using <code>titlecase(str)</code> gives me:</p>
  
  <pre><code>"Operator Fail to Properly Remove Solid Waste"
  </code></pre>
  
  <p>What I need is:</p>
  
  <pre><code>"Operator fail to properly remove solid waste"
  </code></pre>
  
  <p>Is there an easy way to do this?</p>