title: List as key in dictionary
body: <p>I know, i can't put list as key in dictionary in Python.
  I need array of strings, and for each string I need to have some values, that I can access through that string.
  E.g </p>
  
  <pre><code>["string1" : ["string1.1","string1.2","string1.3"], "string2" :["string2.1","string2.2"]]
  </code></pre>
  
  <p>And i need to iterate through strings(string1, string2) and for example print second sub_string(stringX.2) so I get </p>
  
  <pre><code>&gt;&gt;"string1.2","string2.2"
  </code></pre>
  
  <p>What is the best solution for this problem?</p>