title: Is there Multimap in Kotlin?
body: <p>I need to store values in map likie this:</p>
  
  <pre><code> val map = HashMap&lt;String, Set&lt;String&gt;&gt;()
  </code></pre>
  
  <p>But it is hard to interact with Set inside the map.</p>
  
  <p>Is there any multimap implementations in Kotlin like <a href="https://google.github.io/guava/releases/19.0/api/docs/com/google/common/collect/Multimap.html" rel="noreferrer"> Multimap in Google Guava</a>?</p>