[{'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:time_delta = max(df['created_datetime']) - min(df['created_datetime'])\ntime_window = time_delta.components.days*24 + time_delta.components.hours\ntime_lag = timedelta(hours = 6)\ntime_gap = timedelta(hours = 2)\nwindows = int(round(time_delta/time_gap,0))\nprint('start time: ', min(df['created_datetime']),'\\n',\\\n'end time:  ', max(df['created_datetime']),'\\n',\\\n'total hours: ',time_window,'\\n',\\\n'time lag: ', time_lag,'\\n',\\\n'time gap: ', time_gap,'\\n',\\\n'time windows: ', windows)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]