title: write list to CSV
body: <p>I have a list of lists like:</p>
  
  <pre><code>[[A], [B], [A,B], [B], [C], [A, B, C], [C, A]]
  </code></pre>
  
  <p>I want to write it to CSV file like:</p>
  
  <pre><code>A,
  B,
  A,B,
  B,
  C,
  A,B,C,
  C,A,
  </code></pre>
  
  <p>Please consider that I have 556,375 lists and each of them contains minimum 20 variables.</p>