code: def test_text_environment_tool_call_parsing(self):
      string_valid = (
          "Something something <request><Tool1>Hello there!<call>"
      )
      string_invalid_request = (
          "Something something <Tool1>Hello there!<call>"
      )
      string_invalid_call = (
          "Something something <request><Tool1>Hello there!"
      )
      string_invalid_tool = (
          "Something something <request>|Tool2|Hello there!<call>"
      )
      string_invalid_random = "<>abcdefghijklm<>nopqrstuvwxyz<>"
  
      env = TextEnvironment(
          self.gpt2_model,
          self.gpt2_tokenizer,
          tools=[DummyTool()],
          reward_fn=lambda x: torch.tensor(1),
          prompt="I am a prompt!\n",
      )
      tool, response = env.parse_tool_call(string_valid)
      self.assertEqual(tool, "Tool1")
      self.assertEqual(response, "Hello there!")
  
      tool, response = env.parse_tool_call(string_invalid_request)
      self.assertEqual(tool, None)
      self.assertEqual(response, None)
  
      tool, response = env.parse_tool_call(string_invalid_call)
      self.assertEqual(tool, None)
      self.assertEqual(response, None)
  
      tool, response = env.parse_tool_call(string_invalid_tool)
      self.assertEqual(tool, None)
      self.assertEqual(response, None)
  
      tool, response = env.parse_tool_call(string_invalid_random)
      self.assertEqual(tool, None)
      self.assertEqual(response, None)
  
imports: import unittest
  from unittest.mock import patch
  import torch
  from transformers import AutoTokenizer
  from trl import AutoModelForCausalLMWithValueHead, TextEnvironment, TextHistory
label_desc: Use image node_id 4 for calling the TextEnvironmentTester obj's underlying member method code with example usage: obj.test_text_environment_tool_call_parsing() without return types