title: How to merge dictionaries of dictionaries?
body: <p>I need to merge multiple dictionaries, here's what I have for instance:</p>
  
  <pre><code>dict1 = {1:{"a":{A}}, 2:{"b":{B}}}
  
  dict2 = {2:{"c":{C}}, 3:{"d":{D}}
  </code></pre>
  
  <p>With <code>A</code> <code>B</code> <code>C</code> and <code>D</code> being leaves of the tree, like <code>{"info1":"value", "info2":"value2"}</code></p>
  
  <p>There is an unknown level(depth) of dictionaries, it could be <code>{2:{"c":{"z":{"y":{C}}}}}</code></p>
  
  <p>In my case it represents a directory/files structure with nodes being docs and leaves being files.</p>
  
  <p>I want to merge them to obtain:</p>
  
  <pre><code> dict3 = {1:{"a":{A}}, 2:{"b":{B},"c":{C}}, 3:{"d":{D}}}
  </code></pre>
  
  <p>I'm not sure how I could do that easily with Python.</p>