code: def _find_classes_param(self):
          
          for attr in ["classes_"]:
              try:
                  return getattr(self.estimator, attr)
              except AttributeError:
                  continue
  
          raise YellowbrickTypeError(
              "could not find classes_ param on {}".format(
                  self.estimator.__class__.__name__
              )
          )
docs: Searches the wrapped model for the classes_ parameter.