[{'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:# Combining train and test data\n# Decomposing date features\n\ndata['part'] = 'train'\ntest['part'] = 'test'\nall_data = pd.concat([data, test], 0)[data.columns.tolist()+['Id']]\nall_data['Date'] = pd.to_datetime(all_data['Date'])\nall_data['Month'] = all_data['Date'].dt.month\nall_data['Year'] = all_data['Date'].dt.year\nall_data['Day'] = all_data['Date'].dt.day\nall_data['WeekOfYear'] = data.Date.dt.weekofyear\nall_data['Quarter'] = data.Date.dt.quarter\nall_data.sort_values('Date', inplace=True)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]