code: def test_unknown_strategy():
      with pytest.raises(ValueError):
          strategies.generate_trials(
              "unknown_strategy", FLAT_PARAMS, nb_trials=None
          )
  
imports: import pytest
  from test_tube.hyper_opt_utils import strategies
label_desc: Use image node_id 1 for calling a global function with example usage: test_unknown_strategy() without return types