title: How to add new key-value pair into dictionary where value is array of arrays
body: <p>I have this structure of my dictionary in python:</p>
  
  <pre><code>dict={'key1': [['val1','val2'], ['val1','val2'], ['val1','val2']],....}
  </code></pre>
  
  <p>I want to write function for adding new key-value pair. This is the method:</p>
  
  <pre><code>def AddNewPair(key, firstArr, secondArr, thirdArr):
       myDict.update({key:[[firstArr],[secondArr],[thirdArr]]});
  </code></pre>
  
  <p>The example of function call is here:</p>
  
  <pre><code>AddNewPair("key2",["val1","val2"],["val1","val2"],["val1","val2"]);
  </code></pre>
  
  <p>This function works, but not properly. It adds new key value pair almost as expected, but the value (array of arrays) is wrapped with another unnecessary array. So, the result is this:</p>
  
  <pre><code>dict={'key1': [['val1','val2'], ['val1','val2'], ['val1','val2']],'key2': [[['val1','val2'], ['val1','val2'], ['val1','val2']]] }
  </code></pre>
  
  <p>Of course I dont want this wrapped array. Please, can you help me with this? thank you very much.</p>