code: def test_default_for_key_args(self):
      mock = Mock()
  
      class MyMetric(metrics.Metric):
          def __init__(self, *args, **kwargs):
              super(MyMetric, self).__init__("test")
              mock(*args, **kwargs)
  
      default_for_key("test", 10, some_arg="a test")(MyMetric)
      metrics.get_default("test")
      mock.assert_called_once_with(10, some_arg="a test")
  
imports: import unittest
  from mock import Mock
  import torchbearer.metrics
  from torchbearer.metrics import default_for_key, lambda_metric, EpochLambda, BatchLambda
label_desc: Use image node_id 3 for calling the TestDecorators obj's underlying member method code with example usage: obj.test_default_for_key_args() without return types