title: Calculating permutations without repetitions in Python
body: <p>I have two lists of items:</p>
  
  <pre><code>A = 'mno'
  B = 'xyz'
  </code></pre>
  
  <p>I want to generate all permutations, without replacement, simulating replacing all combinations of items in A with items in B, without repetition. e.g.</p>
  
  <pre><code>&gt;&gt;&gt; do_my_permutation(A, B)
  ['mno', 'xno', 'mxo', 'mnx', 'xyo', 'mxy', 'xyz', 'zno', 'mzo', 'mnz', ...]
  </code></pre>
  
  <p>This is straight-forward enough for me to write from scratch, but I'm aware of Python's starndard <a href="http://docs.python.org/2/library/itertools.html" rel="nofollow">itertools module</a>, which I believe may already implement this. However, I'm having trouble identifying the function that implements this exact behavior. Is there a function in this module I can use to accomplish this?</p>