[{'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:labels = train_users['country_destination'].values\ntrain_users = train_users.drop(['country_destination', 'date_first_booking'], axis=1)\ntest_users = test_users.drop(['date_first_booking'], axis=1)\nid_test = test_users['id']\n\n# Merge train and test users\nall_users = pd.concat((train_users, test_users), axis=0, ignore_index=True)\n\n# Remove ID's since now we are not interested in making predictions\nall_users.drop('id',axis=1, inplace=True)\n\nall_users.head()"}, {'role': 'assistant', 'content': 'data_preprocessing'}]