[{'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:raw_train_data['Date'] = pd.to_datetime(raw_train_data['Date'])\ntest_check = raw_train_data[raw_train_data['Date']>'2020-03-18']\nmodel_check = pred_df[pred_df['Date']<=test_check['Date'].max()]"}, {'role': 'assistant', 'content': 'helper_functions'}]