[{'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:# Same thing for the second variable\n# Basic preprocessing which applies to all regression techniques (dependent variable: casual)\ndata = training_set.drop(columns = ['casual', 'count'])\n\nX_train, X_test, y_train, y_test = train_test_split(data, data.registered, test_size=0.2, random_state = RANDOM_STATE)\nX_train = X_train.drop(columns = ['registered'])\nX_test = X_test.drop(columns = ['registered'])"}, {'role': 'assistant', 'content': 'data_preprocessing'}]