code: def test_populated_upgrader_graph(self):
      @torch.jit.script
      def f():
          return 0
  
      buffer = io.BytesIO()
      torch.jit.save(f, buffer)
      buffer.seek(0)
      torch.jit.load(buffer)
      upgraders_size = torch._C._get_upgraders_map_size()
      upgraders_dump = torch._C._dump_upgraders_map()
      # make sure we only populate the upgrader map only once
      # so we load it again and make sure the upgrader map has
      # same content
      buffer.seek(0)
      torch.jit.load(buffer)
      upgraders_size_second_time = torch._C._get_upgraders_map_size()
      upgraders_dump_second_time = torch._C._dump_upgraders_map()
      self.assertTrue(upgraders_size == upgraders_size_second_time)
      self.assertTrue(upgraders_dump == upgraders_dump_second_time)
  
imports: import io
  import os
  import sys
  import torch
  import zipfile
  from torch.testing import FileCheck
  from typing import Union
  from torch.testing._internal.jit_utils import JitTestCase
label_desc: Use image node_id 2 for calling the TestUpgraders obj's underlying member method code with example usage: obj.test_populated_upgrader_graph() and returns: int