title: Python - How to save a list as a constant
body: <p>I started recently Python Language and i have a problem about lists.
  I was surprised not to find what i was looking for by searching on Google, I guess i couldn't explain with the right words because english isn't my native language.
  Here's my problem:</p>
  
  <p>When i create a list and i want to modify it but i want to keep the last value, I don't know how to do.
  I thought that i could save my list in a second list, but when i modify the other list, it doesn't stay constant.</p>
  
  <pre><code>list1=[1,2,3,4]
  list2=list1
  list1.append(5)
  print(list2)
  </code></pre>
  
  <p>For exemple, here, I thought that my list2 will stay constant but no, it is synchronised to the list1 and when I print(list2), the 5 that i added in list1 appears.</p>
  
  <p>I really don't know how to solve this problem, if someone could help me it would be very cool, thanks !</p>