code: def test_target_col_not_dropped():
      X = pd.DataFrame(np.zeros((100, 1)))
      # work-around for pandas 1.0
      X.iloc[-4:] = 1
      types = detect_types(X)
      assert types.useless[0]
      types = detect_types(X, target_col=0)
      assert types.categorical[0]
  
imports: import os
  import pytest
  import random
  import string
  import warnings
  import numpy
  import pandas
  from sklearn.datasets import load_iris, load_digits
  from sklearn.model_selection import train_test_split
  from sklearn.pipeline import make_pipeline
  from sklearn.linear_model import LogisticRegression
  from dabl.preprocessing import USELESS_TYPES, detect_types, EasyPreprocessor, DirtyFloatCleaner, clean, _FLOAT_REGEX, _float_matching, detect_type_series
  from dabl.utils import data_df_from_bunch
  from dabl.datasets import load_titanic
  from dabl import plot
label_desc: Use image node_id 6 for calling a global function with example usage: test_target_col_not_dropped() without return types