title: Check if key exists in multiple maps in one condition
body: <p>I need to check if the same key exists in two maps:</p>
  
  <pre><code>if v1, ok1 := map1["aaa"]; ok1 {
   ...
  }
  if v2, ok2 := map2["aaa"]; ok2 {
   ...
  }
  </code></pre>
  
  <p>Is it possible to join these two conditions into one? I managed to do something like this:</p>
  
  <pre><code>v1, ok1 := map1["aaa"]
  v2, ok2 := map2["aaa"]
  if ok1 &amp;&amp; ok2 {
   ...
  }
  </code></pre>
  
  <p>but I'm curious whether it (assigning and checking) can be done in one <code>if</code> condition.</p>