code: def test_get_validation_batches_invalid_number_of_samples(self):
      patch_size = 3
      with patch("os.listdir", side_effect=self.fake_folders):
          with patch(
              "ISR.utils.datahandler.DataHandler._check_dataset",
              return_value=True,
          ):
              DH = DataHandler(
                  lr_dir={"res": "lr", "matching": True},
                  hr_dir={"res": "hr", "matching": True},
                  patch_size=patch_size,
                  scale=2,
                  n_validation_samples=None,
              )
  
      with patch("imageio.imread", side_effect=self.image_getter):
          with patch("os.path.join", side_effect=self.path_giver):
              try:
                  with patch("raise", None):
                      batch = DH.get_validation_batches(batch_size=5)
              except:
                  self.assertTrue(True)
              else:
                  self.assertTrue(False)
  
imports: import unittest
  import numpy
  from unittest.mock import patch
  from ISR.utils.datahandler import DataHandler
label_desc: Use image node_id 16 for calling the DataHandlerTest obj's underlying member method code with example usage: obj.test_get_validation_batches_invalid_number_of_samples() without return types