title: iterating one key in a python multidimensional associative array
body: <p>I'm dynamically creating a 2 dimensional associative array (dictionary?)</p>
  
  <p>I'm trying to loop through its keys - while keeping one of the indexes constant, so for instance all of the values associated to "key" with 'john' in its first bracket:</p>
  
  <pre><code>myhash['john']['smith'] = "address 1"
  myhash['john']['doe'] = "address 2"
  </code></pre>
  
  <p>how can i get all of the keys of the hash for each "key" keeping the first index as 'john'
  (i want all of the last names)</p>
  
  <p>Thanks</p>