[{'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:stop_words = set(stopwords.words("english"))\ndef bag_of_words(dictionary_with_count,dictionary_ref,dict_ref_src,dict_imed_prev, document, index):\nwords = word_tokenize(document)\nfor w in words:\nif w not in stop_words:\nif w not in dictionary_with_count:\ndictionary_with_count[w] = 1\ndictionary_ref[(index,w)] = 1\ndict_ref_src[w] = index\ndict_imed_prev[w] = index\nelse:\ndictionary_with_count[w] += 1\ntemp_index = dict_ref_src[w]\nif dict_imed_prev[w] != index:\ndictionary_ref[(temp_index,w)] += 1\ndict_imed_prev[w] = index\nreturn dictionary_with_count , dictionary_ref, dict_ref_src , dict_imed_prev\nexclude = set(string.punctuation) - {\'#\'}\nexclude = list(exclude)\nexclude = exclude+[\'•\']'}, {'role': 'assistant', 'content': 'data_preprocessing'}]