title: [python]how to avoid link in list
body: <p>i have a strange issue on my code. i build a list with the expression:</p>
  <pre><code>&gt; my_list = [[0, 1, 2]] * __MAXIC_NUMBER__
  </code></pre>
  <p>but when i change a part of my_list, all the list is changed.</p>
  <p>e.g:</p>
  <pre><code>my_list = [[0, 1, 2]] * 3
  &quot;&quot;&quot; expected:
  [0, 1, 2]
  [0, 1, 2]
  [0, 1, 2]
  &quot;&quot;&quot;
  
  my_list[1, 1] = 5
  
  &quot;&quot;&quot; 
  expected:
  [0, 1, 2]
  [0, 5, 2]
  [0, 1, 2]
  
  realized:
  [0, 5, 2]
  [0, 5, 2]
  [0, 5, 2]
  &quot;&quot;&quot;
  
  &quot;&quot;&quot;
  </code></pre>
  <p>i don't understand why and how to avoid this effect.</p>
  <p>someone have an idea?</p>
  <p>Thank a lot</p>