new_contents: import unittest
  
  import numpy as np
  
  from libact.base.dataset import Dataset
  from libact.labelers import IdealLabeler
  
  
  class TestDatasetMethods(unittest.TestCase):
  
      initial_X = np.arange(15).reshape((5, 3))
      initial_y = np.array([1, 2, 3, 1, 4])
  
      def setup_dataset(self):
          return Dataset(self.initial_X, self.initial_y)
  
      def test_label(self):
          dataset = self.setup_dataset()
          lbr = IdealLabeler(dataset)
          ask_id = lbr.label(np.array([0, 1, 2]))
          self.assertEqual(ask_id, 1)
          ask_id = lbr.label(np.array([6, 7, 8]))
          self.assertEqual(ask_id, 3)
          ask_id = lbr.label([12, 13, 14])
          self.assertEqual(ask_id, 4)
  
  if __name__ == '__main__':
      unittest.main()
  
subject: add test for labelers