code: def _get_2d_dataset(self):
      X_train = gs.array(
          [[0.0, 0.0], [1.0, 0.0], [2.0, 0.0], [3.0, 0.0]]
      )
      y_train = gs.array([0, 0, 1, 1])
      return X_train, y_train
  
file_path: geomstats/tests/tests_geomstats/test_learning/data/kernel_density_estimation_classifier.py
imports: import geomstats.backend
  from geomstats.geometry._hyperbolic import _Hyperbolic
  from geomstats.geometry.euclidean import Euclidean
  from geomstats.geometry.hyperboloid import Hyperboloid
  from geomstats.geometry.hypersphere import Hypersphere
  from geomstats.geometry.poincare_ball import PoincareBall
  from geomstats.learning.kernel_density_estimation_classifier import KernelDensityEstimationClassifier
  from geomstats.learning.radial_kernel_functions import triangular_radial_kernel
  from geomstats.test.data import TestData
label_desc: Use image node_id 2 for calling the KernelDensityEstimationClassifierTestData obj's underlying member method code with example usage: obj._get_2d_dataset() and returns: X_train,  y_train