multiset combinatorics generation : <p>I came across the following problem.</p>

<p>Is there a fast python built-in method to do the following:</p>

<pre><code>Input: sets {1,2}, {3,4}, {6,7,8}

Output: sets {1,3,6}, {1,3,7}, {1,3,8}, {1,4,6}, {1,4,7}, {1,4,8}, {2,3,6}, {2,3,7}, {2,3,8}, {2,4,6}, {2,4,7}, {2,4,8}
</code></pre>

<p>Thanks!</p>
