code: def test_python_en_tokenizer_truncation(self):
      src_text = [
          "def sum(a,b,c):NEW_LINE_INDENTreturn sum([a,b,c])" * 20
      ]
      self.assertIsInstance(src_text[0], str)
      desired_max_length = 10
      ids = self.tokenizer(
          src_text, max_length=desired_max_length, truncation=True
      ).input_ids[0]
      self.assertEqual(ids[-2], 2)
      self.assertEqual(ids[-1], PYTHON_CODE)
      self.assertEqual(len(ids), desired_max_length)
  
imports: import tempfile
  import unittest
  from transformers import SPIECE_UNDERLINE, BatchEncoding, PLBartTokenizer, is_torch_available
  from transformers.testing_utils import get_tests_dir, nested_simplify, require_sentencepiece, require_tokenizers, require_torch
  from ...test_tokenization_common import TokenizerTesterMixin
label_desc: Use image node_id 5 for calling the PLBartPythonEnIntegrationTest obj's underlying member method code with example usage: obj.test_python_en_tokenizer_truncation() without return types