code: def test_gpt2_tokenize_eos(self):
      eos_token: str = "<|endoftext|>"
      tokenizer = HuggingFaceTokenizers.get_tokenizer(
          "huggingface/gpt2"
      )
      token_ids = tokenizer.encode(eos_token)
      assert singleton(token_ids) == 50256
      assert tokenizer.decode(token_ids) == eos_token
  
file_path: H2O/h2o_hf/helm/src/helm/proxy/clients/test_huggingface_tokenizer.py
imports: from helm.common.general import singleton
  from .huggingface_tokenizer import HuggingFaceTokenizers
label_desc: Use image node_id 10 for calling the TestHuggingFaceTokenizers obj's underlying member method code with example usage: obj.test_gpt2_tokenize_eos() without return types