code: def test_FromFidelityEvaluations(self) -> None:
      for sem in (0.5, None):
          eval1 = (3.7, sem) if sem is not None else 3.7
          eval2 = (3.8, sem) if sem is not None else 3.8
          data = Data.from_fidelity_evaluations(
              evaluations={
                  "0_1": [
                      ({"f1": 1.0, "f2": 0.5}, {"b": eval1}),
                      ({"f1": 1.0, "f2": 0.75}, {"b": eval2}),
                  ]
              },
              trial_index=0,
              sample_sizes={"0_1": 2},
              start_time=current_timestamp_in_millis(),
              end_time=current_timestamp_in_millis(),
          )
          self.assertEqual(data.df["sem"].isnull().all(), sem is None)
          self.assertEqual(len(data.df), 2)
          self.assertIn("start_time", data.df)
          self.assertIn("end_time", data.df)
  
imports: import random
  import pandas
  from ax.core.data import clone_without_metrics, custom_data_class, Data, set_single_trial
  from ax.utils.common.testutils import TestCase
  from ax.utils.common.timeutils import current_timestamp_in_millis
label_desc: Use image node_id 9 for calling the DataTest obj's underlying member method code with example usage: obj.test_FromFidelityEvaluations() without return types