title: Plus equals with ruby send message
body: <p>I'm getting familiar with ruby send method, but for some reason, I can't do something like this</p>
  
  <pre><code>a = 4
  a.send(:+=, 1)
  </code></pre>
  
  <p>For some reason this doesn't work. Then I tried something like </p>
  
  <pre><code>a.send(:=, a.send(:+, 1))
  </code></pre>
  
  <p>But this doesn't work too. What is the proper way to fire plus equals through 'send'?</p>