code: def test_nested_function(self):
      def f(x):
          def inner_fn(y):
              if y > 0:
                  return y * y
              else:
                  return y
  
          return inner_fn(x)
  
      self.assertTransformedEquivalent(f, 2)
      self.assertTransformedEquivalent(f, -2)
  
imports: from tensorflow.python.autograph.converters import functions
  from tensorflow.python.autograph.converters import return_statements
  from tensorflow.python.autograph.core import converter_testing
  from tensorflow.python.framework import ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 14 for calling the SingleReturnTest obj's underlying member method code with example usage: obj.test_nested_function() and returns: inner_fn, unknown, y