code: def read(proto):
      
      impl = proto.implementation
      if impl == 'py':
        return SDRClassifier.read(proto.sdrClassifier)
      elif impl == 'cpp':
        return FastSDRClassifier.read(proto.sdrClassifier)
      elif impl == 'diff':
        return SDRClassifierDiff.read(proto.sdrClassifier)
      else:
        raise ValueError('Invalid classifier implementation (%r). Value must be '
                         '"py", "cpp" or "diff".' % impl)
docs: :param proto: SDRClassifierRegionProto capnproto object