code: def test_plugin_does_not_exist():
      def raise_entrypoint_exception(group, name):
          raise entrypoints.NoSuchEntryPoint(group, name)
  
      with mock.patch("entrypoints.get_single") as mock_get_single:
          mock_get_single.side_effect = raise_entrypoint_exception
          backend = loader.load_backend("my_plugin")
          assert backend is None
  
imports: from unittest import mock
  import entrypoints
  from mlflow.projects.backend import loader
label_desc: Use image node_id 2 for calling a global function with example usage: test_plugin_does_not_exist() without return types