code: def test_custom_metric_from_str():
      custom_metric = h2o.upload_custom_metric(
          CustomOneFuncStr,
          class_name="CustomOneFunc",
          func_name="custom_mm",
      )
      (model2, f_test2) = regression_model(
          H2OGradientBoostingEstimator, custom_metric
      )
      assert_all_metrics_equal(model2, f_test2, "custom_mm", 1)
  
imports: import sys
  import h2o
  from tests import pyunit_utils
  from tests.pyunit_utils import CustomOneFuncStr, assert_all_metrics_equal, regression_model
  from h2o.estimators.gbm import H2OGradientBoostingEstimator
label_desc: Use image node_id 1 for calling a global function with example usage: test_custom_metric_from_str() without return types