title: How to merge two dictionaries with same keys and keep values that exist in the same key
body: <p>For example:</p>
  
  <pre><code>Dictionary1={'A' :['B','C','D'],'B' :['A']}
  Dictionary2={'A' :['A','B'],    'B' :['A','F']}
  </code></pre>
  
  <p>And I want this result:</p>
  
  <pre><code>Merge={'A' :['B'],'B' :['A']}
  </code></pre>
  
  <p>because only 'B' is in both dictionaries under 'A' and only 'B' is in both dictionaries under 'B'</p>