code: def test_mean_group_metric(self):
      metric_fn = metrics.mean_group_metric(metrics.accuracy)
      self.assertDictClose(
          metric_fn(
              [
                  {"group": "a", "value": 0},
                  {"group": "a", "value": 1},
                  {"group": "b", "value": 0},
              ],
              [{"value": 0}, {"value": 0}, {"value": 1}],
          ),
          {"accuracy": 25.0},
      )
  
imports: from unittest import mock
  from absl.testing import absltest
  import numpy
  import seqio
  import sklearn.metrics
  from t5.evaluation import metrics
  from t5.evaluation import test_utils
label_desc: Use image node_id 22 for calling the MetricsTest obj's underlying member method code with example usage: obj.test_mean_group_metric() without return types