code: def test_cross_val():
      ft_clf = ColLblBasedFtClassifier("txt", epoch=3)
      ftdf = _big_ftdf()
      cross_val_score(
          ft_clf,
          X=ftdf[["txt"]],
          y=ftdf["lbl"],
          cv=2,
          scoring="accuracy",
      )
  
      ft_clf = IdxBasedFtClassifier(0, epoch=3)
      ftdf = _big_ftdf()
      cross_val_score(
          ft_clf,
          X=ftdf[["txt"]],
          y=ftdf["lbl"],
          cv=2,
          scoring="accuracy",
      )
  
      ft_clf = FirstColFtClassifier(epoch=3)
      ftdf = _big_ftdf()
      cross_val_score(
          ft_clf,
          X=ftdf[["txt"]],
          y=ftdf["lbl"],
          cv=2,
          scoring="accuracy",
      )
  
imports: import pytest
  import pandas
  from sklearn.model_selection import cross_val_score
  from skift import FirstColFtClassifier, IdxBasedFtClassifier, ColLblBasedFtClassifier, FirstObjFtClassifier, SeriesFtClassifier
label_desc: Use image node_id 19 for calling a global function with example usage: test_cross_val() without return types