code: def test_weights_zero():
      knop_test = KNOP()
      competences = np.zeros((1, 3))
      result = knop_test.select(competences)
  
      assert np.all(result)
  
file_path: DESlib/deslib/tests/des/test_knop.py
imports: from unittest.mock import Mock
  import numpy
  import pytest
  from sklearn.linear_model import Perceptron
  from sklearn.utils.estimator_checks import check_estimator
  from deslib.des.knop import KNOP
label_desc: Use image node_id 3 for calling a global function with example usage: test_weights_zero() without return types