[{'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:# extract newest data\ndf_smoking_recent = df_smoking.sort_values('Year', ascending=False).reset_index(drop=True)\ndf_smoking_recent = df_smoking_recent[df_smoking_recent['Entity'].duplicated()==False]\ndf_smoking_recent['Country_Region'] = df_smoking_recent['Entity']\ndf_smoking_recent['SmokingRate'] = df_smoking_recent['Smoking prevalence, total (ages 15+) (% of adults)']\ndf_smoking_recent.head()"}, {'role': 'assistant', 'content': 'data_preprocessing'}]