code: def test_group_exact_counts(self):
      match_groups = ["group_a"]
      self.check_group_counts("group_a", "exact", match_groups)
  
imports: import unittest
  from copy import deepcopy
  from finetune.util.group_metrics import get_count_fn, calc_group_assignment, create_joint_groups, get_metrics, group_metrics, joint_metrics
label_desc: Use image node_id 3 for calling the TestGroupMetricCountFunctions obj's underlying member method code with example usage: obj.test_group_exact_counts() without return types