code: def test_EmptyData(self) -> None:
      df = Data().df
      self.assertTrue(df.empty)
      # pyre-fixme[6]: For 1st param expected `Iterable[Variable[_T]]` but got `bool`.
      self.assertTrue(set(df.columns == Data.REQUIRED_COLUMNS))
      self.assertTrue(Data.from_multiple_data([]).df.empty)
  
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 4 for calling the DataTest obj's underlying member method code with example usage: obj.test_EmptyData() without return types