title: Create custom exception handler for unhandled exceptions in Flask
body: <p>Is there any way in Flask to create a custom function for an unhanded exception?  My real goal is to log the exception and return an HTTP 500 whenever something happens that is unexpected.</p>
  
  <pre><code># Modules
  app = Flask(__name__)
  app.handle_exception = lambda e: 'exception!'
  </code></pre>