code: def test_return_only_prefixed(self):
      parent = counting.Counter()
      child1 = counting.Counter(
          parent, "child1", time_delta=0.0, return_only_prefixed=False
      )
      child2 = counting.Counter(
          parent, "child2", time_delta=0.0, return_only_prefixed=True
      )
      child1.increment(foo=1)
      child2.increment(bar=1)
      self.assertEqual(
          child1.get_counts(), {"child1_foo": 1, "child2_bar": 1}
      )
      self.assertEqual(child2.get_counts(), {"bar": 1})
  
file_path: acme/acme/utils/counting_test.py
imports: import threading
  from acme.utils import counting
  from absl.testing import absltest
label_desc: Use image node_id 4 for calling the CountingTest obj's underlying member method code with example usage: obj.test_return_only_prefixed() without return types