code: def get_dataset(self):
      raise NotImplementedError("get_dataset() must be overridden")
  
imports: import unittest
  import pytest
  import numpy
  from scipy.sparse import csr_matrix
  from sklearn.utils.validation import check_is_fitted
  from small_text.classifiers.classification import ConfidenceEnhancedLinearSVC
  from small_text.classifiers.classification import SklearnClassifier
  from small_text.data.datasets import SklearnDataset
  from tests.utils.datasets import random_matrix_data
label_desc: Use image node_id 1 for calling the _SklearnClassifierBaseTest obj's underlying member method code with example usage: obj.get_dataset() without return types