title: List of Lists to Dictionary of Lists
body: <p>I am having a hard time converting a list of lists to a dictionary of lists due to some of the key values being the same, I am also getting an issue with the null value. My List is:</p>
  
  <pre><code>L = [['shark', ['one']], ['shark',['two']], ['fish', ['one']], ['fish', ['two']], ['fish',[]]]
  </code></pre>
  
  <p>My desired dictionary of lists would be structured like this:</p>
  
  <pre><code>Dic = {'shark': ['one','two'], 'fish':['one', 'two', '0']} 
  </code></pre>
  
  <p>Is there any trick to be able to get the same key values to combine into a dictionary of lists like this?</p>