title: python append two matrix side by side
body: <p>I am having some problem with python.  </p>
  
  <pre><code>    A= [ [1,2,3]
           [4,5,6]
         ]
  
     B = [ [10,11]
           [12,13]
         ]
  </code></pre>
  
  <p>I want to have:</p>
  
  <pre><code>   C = [A B]
       = [ [1,2,3,  10, 11]
           [4,5,6,  12, 13]
         ]
  </code></pre>
  
  <p>How do I do that in python?</p>