code: def test_DFP_is_used(
      example_estimate_competence, create_pool_classifiers
  ):
      (
          X,
          y,
          neighbors,
          _,
          dsel_processed,
          _,
      ) = example_estimate_competence
      safe_k = 3
      ds_test = BaseDS(create_pool_classifiers, DFP=True, safe_k=safe_k)
      ds_test.fit(X, y)
      ds_test.DSEL_processed_ = dsel_processed
  
      DFP_mask = frienemy_pruning_preprocessed(
          neighbors[0, :safe_k], y, dsel_processed
      )
      assert np.array_equal(DFP_mask, np.atleast_2d([1, 1, 0]))
  
imports: import unittest.mock
  from unittest.mock import Mock, MagicMock
  import numpy
  import pytest
  from sklearn.exceptions import NotFittedError
  from sklearn.neighbors import KNeighborsClassifier
  from deslib.base import BaseDS
  from deslib.util.dfp import frienemy_pruning_preprocessed
  from .conftest import create_base_classifier
label_desc: Use image node_id 19 for calling a global function with example usage: test_DFP_is_used(example_estimate_competence, create_pool_classifiers) without return types