code: def test_copy():
      copy = CopyTransformer()
      np.testing.assert_array_equal(X, copy.transform(X))
  
file_path: mlxtend/mlxtend/preprocessing/tests/test_copy_transformer.py
imports: import sys
  import numpy
  from packaging.version import Version
  from scipy.sparse import issparse
  from sklearn import __version__
  from sklearn.datasets import load_iris
  from sklearn.feature_extraction.text import TfidfTransformer
  from sklearn.linear_model import LogisticRegression
  from sklearn.model_selection import GridSearchCV
  from sklearn.pipeline import make_pipeline
  from sklearn.preprocessing import StandardScaler
  from mlxtend.preprocessing import CopyTransformer
  from mlxtend.utils import assert_raises
label_desc: Use image node_id 1 for calling a global function with example usage: test_copy() without return types