[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify code snippets into one of the following categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']."}, {'role': 'user', 'content': 'Identify the single most appropriate category to which the provided code belongs. Provide your response as a single category label without any additional information, commentary, or personal opinions.\\nPython Code:def phrase_to_words(raw_phrase):\n    \n    #remove any html\n    phrase_text = BeautifulSoup(raw_phrase).get_text()\n    \n    #remove non letters\n    letters = re.sub("[^A-Za-z]", " ", phrase_text)\n    \n    #to lowercase\n    lower_letters = letters.lower().split()\n    \n    #remove stopwords\n    stop = set(stopwords.words(\'english\'))\n    meaningful_words = [word for word in lower_letters if word not in stop]\n    \n    return (" ".join(meaningful_words))\''}, {'role': 'assistant', 'content': 'data_preprocessing'}]