code: def test_experimental_warning(self):
      with warnings.catch_warnings(record=True) as w:
          warnings.simplefilter("always")
          self.assertEqual(dummy_function(), "success")
      self.assertEqual(len(w), 1)
  
imports: import unittest
  import warnings
  from datasets.utils import experimental
label_desc: Use image node_id 1 for calling the TestExperimentalFlag obj's underlying member method code with example usage: obj.test_experimental_warning() without return types