text: import unittest
  from data_profiler.profilers.helpers.report_helpers import _prepare_report
  import numpy as np
  import json
  
  class TestReportHelperClass(unittest.TestCase):
      def test_serializable_report(self):
          test_dict = {
              "key_1": {
                  "nested_key_1": {
                      "nested_key_1_2": np.ndarray(1)
                  }
              }
          }
          with self.assertRaises(TypeError):
              json.dumps(test_dict)
          with self.assertRaises(TypeError):
              json.dumps(_prepare_report(test_dict))
          with self.assertRaises(TypeError):
              json.dumps(_prepare_report(test_dict, output_format='not a real one'))
          try:
              x = _prepare_report(test_dict, output_format='serIaliZable')
              json.dumps(x)
          except:
              self.fail('serialize_report not json serializable')
  
  if __name__ == '__main__':
      unittest.main()