code: def fixture_tokenizer():
      tokenizer = AutoTokenizer.from_pretrained(
          "mistralai/Mistral-7B-v0.1"
      )
      tokenizer.add_special_tokens(
          {
              "eos_token": AddedToken(
                  "<|im_end|>",
                  rstrip=False,
                  lstrip=False,
                  normalized=False,
              )
          }
      )
      tokenizer.add_tokens(
          [
              AddedToken(
                  "<|im_start|>",
                  rstrip=False,
                  lstrip=False,
                  normalized=False,
              ),
          ]
      )
  
      return tokenizer
  
file_path: axolotl/tests/prompt_strategies/test_sharegpt.py
imports: import pytest
  from datasets import Dataset
  from tokenizers import AddedToken
  from transformers import AutoTokenizer
  from axolotl.datasets import TokenizedPromptDataset
  from axolotl.prompt_strategies.sharegpt import SimpleShareGPTPromptTokenizingStrategy
  from axolotl.prompters import ShareGPTPrompterV2
label_desc: Use image node_id 2 for calling a global function with example usage: fixture_tokenizer() and returns: tokenizer