title: How to add element to matrix?
body: <p>I saw many posts on the same issue but using <code>numpy.array</code>, whereas here I am talking about <code>numpy.matrix</code>. How can I add an element to a matrix? </p>
  
  <p>For example: </p>
  
  <pre><code>my_matrix = [[1 2 3 4 5]]
  </code></pre>
  
  <p>How can I make it: </p>
  
  <pre><code>my_matrix = [[1 2 3 4 5 6]]?
  </code></pre>