code: def test_show_arrow_pipeline():
      """Show arrow in pipeline for top level in pipeline"""
      pipe = Pipeline(
          [
              ("scale", StandardScaler()),
              ("log_Reg", LogisticRegression()),
          ]
      )
  
      html_output = estimator_html_repr(pipe)
      assert (
          'class="sk-toggleable__label  sk-toggleable__label-arrow ">&nbsp;&nbsp;Pipeline'
          in html_output
      )
  
imports: import html
  import locale
  import re
  from contextlib import closing
  from io import StringIO
  from unittest.mock import patch
  import pytest
  from sklearn import config_context
  from sklearn.base import BaseEstimator
  from sklearn.cluster import AgglomerativeClustering, Birch
  from sklearn.compose import ColumnTransformer, make_column_transformer
  from sklearn.datasets import load_iris
  from sklearn.decomposition import PCA, TruncatedSVD
  from sklearn.ensemble import StackingClassifier, StackingRegressor, VotingClassifier
  from sklearn.feature_selection import SelectPercentile
  from sklearn.gaussian_process.kernels import ExpSineSquared
  from sklearn.impute import SimpleImputer
  from sklearn.kernel_ridge import KernelRidge
  from sklearn.linear_model import LogisticRegression
  from sklearn.model_selection import RandomizedSearchCV
  from sklearn.multiclass import OneVsOneClassifier
  from sklearn.neural_network import MLPClassifier
  from sklearn.pipeline import FeatureUnion, Pipeline, make_pipeline
  from sklearn.preprocessing import OneHotEncoder, StandardScaler
  from sklearn.svm import LinearSVC, LinearSVR
  from sklearn.tree import DecisionTreeClassifier
  from sklearn.utils._estimator_html_repr import _get_css_style, _get_visual_block, _HTMLDocumentationLinkMixin, _write_label_html, estimator_html_repr
  from sklearn.utils.fixes import parse_version
label_desc: Use image node_id 16 for calling a global function with example usage: test_show_arrow_pipeline() without return types