code: def test_detect_constant():
      X = pd.DataFrame(
          {
              "a": [0, 0, 0, 0],
              "second": ["no", "no", "no", "no"],
              "b": [0.0, 0.0, 0.0, 0],
              "weird": ["0", "0", "0", "0"],
          }
      )
      res = detect_types(X)
      assert res.useless.sum() == 4
  
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 5 for calling a global function with example usage: test_detect_constant() without return types