[{'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 adding_new_features(df):\n    df.loc[:,'mean_rooms'] = df.loc[:,'total_rooms']/df.loc[:,'households']\n    df.loc[:,'rooms_per_person'] = df.loc[:,'total_rooms']/df.loc[:,'population']\n    df.loc[:,'mean_bedrooms'] = df.loc[:,'total_bedrooms']/df.loc[:,'households']\n    df.loc[:,'bedrooms_per_person'] = df.loc[:,'total_bedrooms']/df.loc[:,'households']\n    df.loc[:,'persons_per_household'] = df.loc[:,'population']/df.loc[:,'households']\n    df.loc[:, 'median_income_per_person'] = df.loc[:,'median_income']/df.loc[:,'persons_per_household']\nadding_new_features(train_data)\nadding_new_features(test_data)\ntrain_data\n\n\n"}, {'role': 'assistant', 'content': 'data_preprocessing'}]