code: def test_run_empty_prompt(self, pipeline_mock):
      generator = HuggingFaceLocalGenerator(
          model="google/flan-t5-base",
          task="text2text-generation",
          generation_kwargs={"max_new_tokens": 100},
      )
  
      generator.warm_up()
  
      results = generator.run(prompt="")
  
      assert results == {"replies": []}
  
imports: from unittest.mock import patch, Mock
  import pytest
  import torch
  from transformers import PreTrainedTokenizerFast
  from haystack.components.generators.hugging_face_local import HuggingFaceLocalGenerator, StopWordsCriteria
label_desc: Use image node_id 19 for calling the TestHuggingFaceLocalGenerator obj's underlying member method code with example usage: obj.test_run_empty_prompt(pipeline_mock) without return types