code: def testPadding(self):
      self.assertEqual(
          [[1, 2, 3], [1, 0, 0]],
          utils.pad([[1, 2, 3], [1]], pad_token=0),
      )
      self.assertEqual(
          [[[1], [2], [3]], [[1], [0], [0]]],
          utils.pad([[[1], [2], [3]], [[1]]], pad_token=0),
      )
      self.assertEqual(
          [[1, 2, 3, 4, 5, 6, 7], [9, 9, 9, 9, 9, 9, 9]],
          utils.pad([[1, 2, 3, 4, 5, 6, 7], []], pad_token=9),
      )
  
file_path: pytext/pytext/data/test/utils_test.py
imports: import unittest
  from pytext.data import utils
label_desc: Use image node_id 1 for calling the PaddingTest obj's underlying member method code with example usage: obj.testPadding() without return types