title: instance variable not modified in a for loop
body: <p>I have a class with instance variables which I want to modify in a loop using a class method, simplified version of what I'm doing:</p>
  
  <pre><code>class Example:
      def __init__(self,x,z):
          self.x=x
          self.z=z
  
      def run(self,y):
  
          temp_list=[self.x, self.z]
  
          for ind,item in enumerate(temp_list):
              temp_list[ind] = temp_list[ind]+y
  
          print (self.x, self.z)
  
  ex = Example(5,6)
  ex.run(5)
  </code></pre>
  
  <p>The output I get is [5,6] instead of the desired [10,11].
  I was wondering if anyone could point me to an explanation as to why this happens?</p>