code: def test_unknown_solver(gbsg2, solver):
      x, y = gbsg2
      m = MinlipSurvivalAnalysis(solver=solver)
  
      msg = r"The 'solver' parameter of MinlipSurvivalAnalysis must be a str among \{.+\}\. Got .+ instead\."
      with pytest.raises(ValueError, match=msg):
          m.fit(x, y)
  
imports: import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_equal
  import pytest
  from sklearn.exceptions import ConvergenceWarning
  from sklearn.preprocessing import scale
  from sksurv.column import encode_categorical
  from sksurv.datasets import load_gbsg2
  from sksurv.exceptions import NoComparablePairException
  from sksurv.svm._minlip import create_difference_matrix
  from sksurv.svm.minlip import HingeLossSurvivalSVM, MinlipSurvivalAnalysis
  from sksurv.testing import FixtureParameterFactory, assert_cindex_almost_equal
  from sksurv.util import Surv
label_desc: Use image node_id 11 for calling a global function with example usage: test_unknown_solver(gbsg2, solver) without return types