[{'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:GLE1=pd.to_datetime(['2012-05-17 01:55','2012-05-17 08:00'] , utc=True)\nGLE1_begin=pd.to_datetime('2012-05-16 12:00', utc=True)\nGLE1_end=pd.to_datetime('2012-05-18 00:00', utc=True)\nGLE2=pd.to_datetime(['2014-01-06 08:15', '2014-01-06 16:15'], utc=True)\nGLE2_begin=pd.to_datetime('2014-01-06 00:00', utc=True)\nGLE2_end=pd.to_datetime('2014-01-07 12:00', utc=True)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]