title: Dictionary - Object referenced not set to an instance of an object
body: <p>I'm trying to hold a lobby system inside of a dictionary.</p>
  
  <pre><code>private Dictionary&lt;string, Dictionary&lt;string, string&gt;&gt; lobbys;
  </code></pre>
  
  <p>The first string being the Lobby ID, and the dictionary within the dictionary holding the clients usernames in the lobby.</p>
  
  <p>When I try to create a new 'lobby' in the dictionary like so:</p>
  
  <pre><code>lobbys.Add("dSd244SfasdD", null);
  </code></pre>
  
  <p>( the "dSd244SfasdD" being the unique lobby ID, and null being the null dictionary I've yet to create (since theres no users in it yet))</p>
  
  <p>I get this error: "Object referenced not set to an instance of an object."</p>
  
  <p>I'm unsure as to what I'm doing wrong, and I'm fairly new to C#. Please help. Thanks :)</p>