code: def is_fitted(self):
      return (
          hasattr(self.model, "n_samples_fit_")
          and self.model.n_samples_fit_ is not None
          and self.model.n_samples_fit_ > 0
      )
  
imports: import logging
  import os
  import numpy
  import sklearn
  from sklearn.base import ClassifierMixin, RegressorMixin
  from sklearn.model_selection import train_test_split
  from sklearn.neighbors import KNeighborsClassifier, KNeighborsRegressor
  from supervised.algorithms.algorithm import BaseAlgorithm
  from supervised.algorithms.registry import BINARY_CLASSIFICATION, MULTICLASS_CLASSIFICATION, REGRESSION, AlgorithmsRegistry
  from supervised.algorithms.sklearn import SklearnAlgorithm
  from supervised.utils.config import LOG_LEVEL
label_desc: Use image node_id 2 for calling the KNNFit obj's underlying member method code with example usage: obj.is_fitted() and returns: unknown