code: def test_global(self):
      def test_fn():
          global global_a
          global global_b
          if global_a:
              global_b = []
          return global_a, global_b
  
      node = self._parse_and_analyze(test_fn)
      fn_body = node.body
  
      self.assertHasDefs(fn_body[2].test, 1)
      self.assertHasDefs(fn_body[2].body[0].targets[0], 1)
      self.assertHasDefs(fn_body[3].value.elts[0], 1)
      self.assertHasDefs(fn_body[3].value.elts[1], 2)
  
      self.assertSameDef(fn_body[2].test, fn_body[3].value.elts[0])
  
      self.assertHasDefinedIn(fn_body[2], ("global_a", "global_b"))
  
imports: from tensorflow.python.autograph.pyct import anno
  from tensorflow.python.autograph.pyct import cfg
  from tensorflow.python.autograph.pyct import naming
  from tensorflow.python.autograph.pyct import parser
  from tensorflow.python.autograph.pyct import qual_names
  from tensorflow.python.autograph.pyct import transformer
  from tensorflow.python.autograph.pyct.static_analysis import activity
  from tensorflow.python.autograph.pyct.static_analysis import reaching_definitions
  from tensorflow.python.platform import test
label_desc: Use image node_id 19 for calling the ReachingDefinitionsAnalyzerTest obj's underlying member method code with example usage: obj.test_global() and returns: global_a,  global_b