title: How do I pass a variable by reference?
body: <p>Are parameters passed by reference or by value? How do I pass by reference so that the code below outputs <code>'Changed'</code> instead of <code>'Original'</code>?</p>
  <pre><code>class PassByReference:
      def __init__(self):
          self.variable = 'Original'
          self.change(self.variable)
          print(self.variable)
  
      def change(self, var):
          var = 'Changed'
  </code></pre>