title: How to find combination of n elements from list of lists while choosing single element for each list
body: <p>Looking for combinations for n elements from list of lists but choosing only one element from each list. E.g.</p>
  <pre><code>list =  [[a, b], [c,d], [e,f,g,h,i], [j,k,l,m, n], [o,p]..]
  </code></pre>
  <p>While choosing no more than one element from each list, I am trying to come up with different combinations</p>
  <p>e.g: for combination of <code>n = 2</code> elements:</p>
  <pre><code>[a,c] [b,c], [c,j]...so on
  </code></pre>
  <p>for combination of <code>n = 3</code> elements:</p>
  <pre><code>[a,c,e], [a,d,f]..so on
  </code></pre>
  <p>for combination of <code>n = 4</code> elements:</p>
  <pre><code>[a, c, j, o], [a,c, i, p] ...
  </code></pre>
  <p>I tried using itertools combinations, but quickly running into issues. Any hints?</p>