title: why can't return assignment statement
body: <p>In IDLE,
  I write a function and intend to return a value. but it can't return</p>
  
  <pre><code>&gt;&gt;&gt; def grade(value):
      if value &gt; 100:
          return (value=100)
      if value &lt;0:
          return (value=0)
  
  SyntaxError: invalid syntax
  </code></pre>
  
  <p>why can't return? but when I change to</p>
  
  <pre><code>value = 100
  return value
  </code></pre>
  
  <p>It can work</p>