title: Unable to get repr for <class xlwings.main.Sheet>
body: <p>When examining a debug trace in PyCharm for the xlwings <a href="https://www.xlwings.org/examples" rel="nofollow noreferrer">Fibonacci</a> example, I get the following message against the following line of code:</p>
  
  <p><code>sht = xw.Book.caller().sheets[0]</code> <em>Unable to get repr for <code>&lt;class xlwings.main.Sheet&gt;</code></em> </p>
  
  <p>The code appears to run correctly, but can someone explain what the message means?</p>
  
  <p>(python 3.6 and xlwings 0.11.4)</p>