code: def test_nested_function_in_control_flow(self):
      def f(x):
          if x:
  
              def inner_fn(y):
                  return y
  
              inner_fn(x)
  
      self.assertTransformedEquivalent(f, 2)
      self.assertTransformedEquivalent(f, -2)
  
imports: from nvidia.dali._autograph.converters import functions
  from nvidia.dali._autograph.converters import return_statements
  from nvidia.dali._autograph.core import converter_testing
label_desc: Use image node_id 15 for calling the SingleReturnTest obj's underlying member method code with example usage: obj.test_nested_function_in_control_flow() and returns: y