title: How to use setup_class to define a variable to be accessed in all methods of class
body: <p>I need to define a variable in a fixture method setup_class for pytest like </p>
  
  <pre><code>class testClassForPytest:
    @classmethod
    def setup_class(cls):
      m = aClassInstance(classInput)
  
    def test_case_1(self):
      #use of the instance m with a method of its class
  </code></pre>
  
  <p>I tried above approach but wasn't able to use the instance m.</p>