[{'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:agebtw0n19= age_gender[(age_gender.age_bucket=='0-4') | (age_gender.age_bucket=='5-9') | (age_gender.age_bucket=='10-14')|(age_gender.age_bucket=='15-19')]\nagebtw49n34= age_gender[(age_gender.age_bucket=='45-49') | (age_gender.age_bucket=='40-44') | (age_gender.age_bucket=='35-39') | (age_gender.age_bucket=='30-34')]\nagebtw99n50= age_gender[(age_gender.age_bucket=='95-99') | (age_gender.age_bucket=='90-94') | (age_gender.age_bucket=='85-89') | (age_gender.age_bucket=='80-84') | (age_gender.age_bucket=='75-79') | (age_gender.age_bucket=='70-74') | (age_gender.age_bucket=='70-74') | (age_gender.age_bucket=='65-69') | (age_gender.age_bucket=='60-64') | (age_gender.age_bucket=='55-59') | (age_gender.age_bucket=='50-54') ]\nagebtw20n29= age_gender[(age_gender.age_bucket=='25-29') | (age_gender.age_bucket=='20-24')]\n"}, {'role': 'assistant', 'content': 'data_preprocessing'}]