class_docstr: Tests for gov_report dataset.
code: def test_flatten_structures_whitespace(self):
      self.assertEqual(
          gov_report._flatten_structure(
              json.loads(_REPORT), " ", 1, False
          ),
          " Introduction p1 p2 Background p3 Conclusion p6",
      )
  
imports: import json
  import tensorflow_datasets.public_api
  from tensorflow_datasets.summarization.gov_report import gov_report
label_desc: Use image node_id 1 for calling the GovReportTest obj's underlying member method code with example usage: obj.test_flatten_structures_whitespace() without return types