code: def test_report_empty(self):
      report = pipeline_dp.ExplainComputationReport()
      with self.assertRaisesRegex(
          ValueError, "The report_generator is not set"
      ):
          report.text()
  
file_path: pipelinedp/tests/report_generator_test.py
imports: import unittest
  import pipeline_dp
  from pipeline_dp.aggregate_params import AggregateParams, Metrics
  from pipeline_dp.report_generator import ReportGenerator
label_desc: Use image node_id 1 for calling the ExplainComputationReportTest obj's underlying member method code with example usage: obj.test_report_empty() without return types