old_contents: class A:
      pass
  
  class B(A):
      def meth_b1(self):
          pass
      def meth_b2(self):
          pass
  
      def meth_a1(self, name = {}):
          pass
  
      def meth_a2(self):
          pass
  
  class D(A):
      def meth_d1(self):
          pass
  
      def meth_a1(self, name = {}):
          pass
  
      def meth_a2(self):
          pass
  
new_contents: class A:
      pass
  
  class B(A):
      def meth_b1(self):
          pass
      def meth_b2(self):
          pass
  
      def meth_a1(self, name = {}):
          pass
  
      def meth_a2(self):
          pass
  
  class D(A):
      def meth_d1(self):
          pass
  
      def meth_a1(self, name = {}):
          pass
  
      def meth_a2(self):
          pass
subject: fix testdata