title: Remove a value from hashmap based on key
body: <p>So, I have a <code>HashMap&lt;String, String&gt;</code></p>
  
  <pre><code>public HashMap&lt;String, String&gt; frozen = new HashMap&lt;String, String&gt;();
  </code></pre>
  
  <p>and I want to remove a value from it depending on the key. So lets say I put in these</p>
  
  <pre><code>frozen.put("1", "1_1");
  frozen.put("1", "1_2");
  </code></pre>
  
  <p>I want to remove only one of the values, not the whole keyset.</p>
  
  <p>How would I go about doing this? If you still didn't understand, this non-existing method should explain it.</p>
  
  <pre><code>frozen.remove("1", "1_2");
  </code></pre>
  
  <p>Obviously that doesn't exist, but that's what I want.</p>
  
  <p>Thanks in advance.</p>