code: def test_empty_edf_info() -> None:
      def _assert_empty(info: _EDFInfo) -> None:
          assert info.lines == []
          np.testing.assert_array_equal(info.x_values, np.array([]))
  
      edf_info = _get_edf_info([])
      _assert_empty(edf_info)
  
      study = create_study()
      edf_info = _get_edf_info(study)
      _assert_empty(edf_info)
  
      trial = study.ask()
      study.tell(trial, state=optuna.trial.TrialState.PRUNED)
      edf_info = _get_edf_info(study)
      _assert_empty(edf_info)
  
imports: from __future__ import annotations
  from io import BytesIO
  from typing import Any
  from typing import Callable
  import numpy
  import pytest
  import optuna
  from optuna import Study
  from optuna.study import create_study
  from optuna.testing.visualization import prepare_study_with_trials
  from optuna.trial import create_trial
  from optuna.visualization import plot_edf
  from optuna.visualization._edf import _EDFInfo
  from optuna.visualization._edf import _get_edf_info
  from optuna.visualization._edf import NUM_SAMPLES_X_AXIS
  from optuna.visualization._plotly_imports import _imports
  from optuna.visualization.matplotlib import plot_edf
  from optuna.visualization.matplotlib._matplotlib_imports import _imports
label_desc: Use image node_id 9 for calling a global function with example usage: test_empty_edf_info() without return types