title: Yield in Implicitly Defined Generator?
body: <p>In <a href="https://docs.python.org/3.7/reference/expressions.html#generator-expressions" rel="nofollow noreferrer">Generator expressions</a>, it says</p>
  
  <blockquote>
    <p>To avoid interfering with the expected operation of the generator expression itself, yield and yield from expressions are prohibited in the implicitly defined generator</p>
  </blockquote>
  
  <p>What does this mean?</p>