code: def test_sum(self) -> None:
      a = Stats(my_int_metric=1, my_float_metric=0.1, count=1)
      b = Stats(my_int_metric=2, my_float_metric=0.0, count=2)
      c = Stats(my_int_metric=0, my_float_metric=0.2, count=2)
      self.assertEqual(
          Stats.sum([a, b, c]),
          Stats(
              my_int_metric=3,
              my_float_metric=0.30000000000000004,
              count=5,
          ),
      )
  
imports: from unittest import main, TestCase
  from torchbiggraph.stats import Stats
label_desc: Use image node_id 1 for calling the TestConfig obj's underlying member method code with example usage: obj.test_sum() without return types