code: def test_fista_custom_prox(data, request):
      # test FISTA with a custom prox
      l1_pen = L1Penalty()
      X, y = request.getfixturevalue(data)
      clf = FistaClassifier(max_iter=500, penalty="l1", max_steps=0)
      clf.fit(X, y)
  
      clf2 = FistaClassifier(max_iter=500, penalty=l1_pen, max_steps=0)
      clf2.fit(X, y)
      np.testing.assert_array_almost_equal_nulp(
          clf.coef_.ravel(), clf2.coef_.ravel()
      )
  
imports: import numpy
  import pytest
  from scipy.linalg import svd, diagsvd
  from lightning.classification import FistaClassifier
  from lightning.regression import FistaRegressor
  from lightning.impl.penalty import project_simplex, L1Penalty
label_desc: Use image node_id 17 for calling a global function with example usage: test_fista_custom_prox(data, request) without return types