Ops returned from a model_fn.
THIS CLASS IS DEPRECATED. See contrib/learn/README.md for general migration instructions.
Creates an equivalent
default_serving_output_alternative_key: Required for multiple heads. If you have multiple entries in
output_alternativesdict (comparable to multiple heads),
EstimatorSpecrequires a default head that will be used if a Servo request does not explicitly mention which head to infer on. Pass the key of the output alternative here that you want to designate as default. A separate ExportOutpout for this default head will be added to the export_outputs dict with the special key saved_model.DEFAULT_SERVING_SIGNATURE_DEF_KEY, unless there is already an enry in output_alternatives with this special key.
EstimatorSpec that is equivalent to this
ValueError: If problem type is unknown.