[{'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:yemen_data['gender'] = (yemen_data.replace(to_replace = [1,2],\nvalue=[1,\n2]).gender)\nyemen_data['level_of_education'] = (yemen_data.replace(to_replace = [1,2,3,4,5],\nvalue=[1,\n2,\n3,\n4,\n5]).level_of_education)\nyemen_data['employment'] = (yemen_data.replace(to_replace = [1,2,3],\nvalue=[1,\n2,\n3]).employment)\nyemen_data['urban_or_rural'] = (yemen_data.replace(to_replace = [1,2,4],\nvalue=[1,\n2,\n0]).urban_or_rural)\nyemen_data['age']  = (yemen_data.replace(to_replace = [1,2,3,4,5],\nvalue=[1,\n2,\n3,\n4,\n5]).age)\nyemen_data['region'] = (yemen_data.replace(to_replace = [1,2,3,4,5,6],\nvalue=[1,\n2,\n3,\n4,\n5,\n6]).region)"}, {'role': 'assistant', 'content': 'data_preprocessing'}]