code: def test_isotonic_copy_before_fit():
      # https://github.com/scikit-learn/scikit-learn/issues/6628
      ir = IsotonicRegression()
      copy.copy(ir)
  
imports: import copy
  import pickle
  import warnings
  import numpy
  import pytest
  from scipy.special import expit
  import sklearn
  from sklearn.datasets import make_regression
  from sklearn.isotonic import IsotonicRegression, _make_unique, check_increasing, isotonic_regression
  from sklearn.utils import shuffle
  from sklearn.utils._testing import assert_allclose, assert_array_almost_equal, assert_array_equal
  from sklearn.utils.validation import check_array
label_desc: Use image node_id 28 for calling a global function with example usage: test_isotonic_copy_before_fit() without return types