code: def test_color_map(direction: str) -> None:
      study = create_study(directions=[direction, direction])
      for i in range(3):
          study.add_trial(
              create_trial(
                  values=[float(i), float(i)],
                  params={"param_a": 1.0, "param_b": 2.0},
                  distributions={
                      "param_a": FloatDistribution(0.0, 3.0),
                      "param_b": FloatDistribution(0.0, 3.0),
                  },
              )
          )
  
      # Since `plot_pareto_front`'s colormap depends on only trial.number,
      # `reversecale` is not in the plot.
      marker = plot_pareto_front(study).data[0]["marker"]
      assert COLOR_SCALE == [v[1] for v in marker["colorscale"]]
      assert "reversecale" not in marker
  
imports: from __future__ import annotations
  from io import BytesIO
  from typing import Any
  from typing import Callable
  from typing import Sequence
  import warnings
  import pytest
  import optuna
  from optuna import create_study
  from optuna import create_trial
  from optuna.distributions import FloatDistribution
  from optuna.study.study import Study
  from optuna.trial import FrozenTrial
  from optuna.visualization import plot_pareto_front
  import optuna.visualization._pareto_front
  from optuna.visualization._pareto_front import _get_pareto_front_info
  from optuna.visualization._pareto_front import _ParetoFrontInfo
  from optuna.visualization._plotly_imports import go
  from optuna.visualization._utils import COLOR_SCALE
  from optuna.visualization.matplotlib._matplotlib_imports import plt
  import optuna.visualization.matplotlib._pareto_front
label_desc: Use image node_id 14 for calling a global function with example usage: test_color_map(direction) without return types