code: def metric(self):
      try:
          return getattr(self, "_metric")
      except AttributeError:
          invalidInputError(False, "Attribute 'metric' must be set.")
  
file_path: BigDL/python/nano/src/bigdl/nano/deps/neural_compressor/core/base_metric.py
imports: from abc import ABC, abstractmethod
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 2 for calling the BaseINCMetric obj's underlying member method code with example usage: obj.metric() and returns: getattr