[{'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:k=30\ni=0\nfor date in dates:\n    k = k-1\n    i = i+1\n    test.loc[(test['Country_Region']=='China')&(test['Province_State']=='Hubei')&(test['Date']==date),'ConfirmedCases_x']= last_amount.values[0]\n    test.loc[(test['Country_Region']=='China')&(test['Province_State']=='Hubei')&(test['Date']==date),'Fatalities_x']= last_fat.values[0] + i "}, {'role': 'assistant', 'content': 'data_preprocessing'}]