[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify the code snippets into categories from the provided list of categories. List of categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']"}, {'role': 'user', 'content': "Identify to which category the provided code belongs and assign the code snippet to at least 1 but up to 5 categories based on the probabilities, ignore if the probability of the category is negligible. Strictly provide your response as a list. Avoid providing any additional information, commentary, or personal opinions.\\nPython Code:df_us = df_train[df_train['Country_Region']=='US']\ndf_us['Date'] = df_us['Date'].astype(str)\ndf_us['state_code'] = df_us.apply(lambda x: us_state_abbrev.get(x.Province_State,float('nan')), axis=1)\ndf_us['ln(ConfirmedCases)'] = np.log(df_us.ConfirmedCases + 1)\ndf_us['ln(Fatalities)'] = np.log(df_us.Fatalities + 1)"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]