title: "pickBy" the value in the value array of an object
body: <p>I have an object that looks like:</p>
  
  <pre><code>let documents = {"A": [{"document":"test1", "serial":"123"}, {"document":"test2", "serial":"456N"}], "B": [{"document":"test3", "serial":"789N"}, {"document":"test24, "serial":"012"}]};
  </code></pre>
  
  <p>I was trying to get a filtered object that has serial number ending with "N":</p>
  
  <pre><code>{"A": [{"document":"test2", "serial":"456N"}, "B": [{"document":"test3", "serial":"789N"}]}
  </code></pre>
  
  <p>I was doing:</p>
  
  <pre><code> let result = _.pickBy(documents, (docObjs, client) =&gt; {
         return _.filter(docObjs, ({serial}) =&gt; {
           return _.endsWith(serial, 'N');
         });
   });
  </code></pre>
  
  <p>But what I got was the original object (same as <code>documents</code>). Is there anything wrong?</p>