[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify the code snippets into categories from the provided list of categories. List of categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']"}, {'role': 'user', 'content': "Identify to which category the provided code belongs and assign the code snippet to at least 1 but up to 5 categories based on the probabilities, ignore if the probability of the category is negligible. Strictly provide your response as a list. Avoid providing any additional information, commentary, or personal opinions.\\nPython Code:dac = np.vstack(\n    X.date_account_created.astype(str).apply(\n        lambda x: list(map(int, x.split('-')))\n    ).values\n)\nX['dac_year'] = dac[:, 0]\nX['dac_month'] = dac[:, 1]\nX['dac_day'] = dac[:, 2]\nX = X.drop(['date_account_created'], axis=1)\nX.head()"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]