code: def test_return_indices_for_reber_classification(self):
      words, _ = make_reber_classification(100, return_indices=True)
  
      min_index = np.min([np.min(word) for word in words])
      max_index = np.max([np.max(word) for word in words])
  
      self.assertEqual(min_index, 0)
      self.assertEqual(max_index, len(avaliable_letters) - 1)
  
file_path: neupy/tests/datasets/test_reber.py
imports: import math
  import numpy
  from neupy.datasets.reber import avaliable_letters
  from neupy.datasets import make_reber, is_valid_by_reber, make_reber_classification
  from base import BaseTestCase
label_desc: Use image node_id 5 for calling the ReberTestCase obj's underlying member method code with example usage: obj.test_return_indices_for_reber_classification() without return types