code: def fit(self, X, labels):
      self.X = X
      self.labels = labels
      self.tree = spatial.cKDTree(self.X)
  
file_path: scikit-image/skimage/future/tests/test_trainable_segmentation.py
imports: from functools import partial
  import numpy
  import pytest
  from scipy import spatial
  from skimage.future import fit_segmenter, predict_segmenter, TrainableSegmenter
  from skimage.feature import multiscale_basic_features
label_desc: Use image node_id 1 for calling the DummyNNClassifier obj's underlying member method code with example usage: obj.fit(X, labels) without return types