title: Update the values of multiple keys
body: <p>If you have a map or a collection of maps and you'd like to be able to update the values of several keys with one function, what the the most idiomatic way of doing this?</p>
  
  <pre><code>=&gt; (def m [{:a 2 :b 3} {:a 2 :b 5}])
  #'user/m
  =&gt; (map #(update-in % [:a] inc) m)
  ({:a 3, :b 3} {:a 3, :b 5})
  </code></pre>
  
  <p>Rather than mapping update-in for each key, I'd ideally like some function that operates like this:</p>
  
  <pre><code>=&gt; (map #(update-vals % [:a :b] inc) m)
  ({:a 3, :b 4} {:a 3, :b 6})
  </code></pre>
  
  <p>Any advice would be much appreciated! I'm trying to reduce the number of lines in an unnecessarily long script.</p>