class_docstr: A model for testing batched predictions with a minibatch size of 3.
code: def output_spec(self):
      return {"scores": types.RegressionScore()}
  
imports: from absl.testing import absltest
  from absl.testing import parameterized
  from lit_nlp.api import dataset
  from lit_nlp.api import model
  from lit_nlp.api import types
label_desc: Use image node_id 5 for calling the _BatchingTestModel obj's underlying member method code with example usage: obj.output_spec() and returns: dict