code: def test_size(self):
      self.assertEqual(repr(units.Size()), "Unknown size")
      self.assertEqual(repr(units.Size(150)), "150 bytes")
      self.assertEqual(repr(units.Size(1.5 * units.GiB)), "1.50 GiB")
      self.assertEqual(repr(units.Size(150) + 150), "300 bytes")
      self.assertEqual(repr(units.Size(300) - 150), "150 bytes")
      self.assertEqual(str(units.Size()), "Unknown size")
      self.assertEqual(str(units.Size(150)), "150 bytes")
      x = units.Size(300)
      x += 300
      self.assertEqual(repr(x), "600 bytes")
  
imports: from tensorflow_datasets import testing
  from tensorflow_datasets.core import units
label_desc: Use image node_id 4 for calling the UnitsTest obj's underlying member method code with example usage: obj.test_size() without return types