code: def test_model_type_mapper_custom():
      LossModelTypeMapper().register_loss("test", ModelType.REGRESSION)
      assert (
          LossModelTypeMapper().get_model_type("test")
          == ModelType.REGRESSION
      )
  
imports: import pytest
  from elephas.utils.model_utils import ModelType, LossModelTypeMapper
label_desc: Use image node_id 2 for calling a global function with example usage: test_model_type_mapper_custom() without return types