[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify the code snippets into categories from the provided list of categories. List of categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']"}, {'role': 'user', 'content': 'Identify to which category the provided code belongs and assign the code snippet to at least 1 but up to 5 categories based on the probabilities, ignore if the probability of the category is negligible. Strictly provide your response as a list. Avoid providing any additional information, commentary, or personal opinions.\\nPython Code:train[\'P29\'] = train[\'P29\'].astype(int)\ntest[\'P29\']    = test[\'P29\'].astype(int)\ntest["P29"].fillna(test["P29"].median(), inplace=True)\ntrain[\'P26\'] = train[\'P26\'].astype(int)\ntest[\'P26\']    = test[\'P26\'].astype(int)\ntrain[\'P27\'] = train[\'P27\'].astype(int)\ntest[\'P27\']    = test[\'P27\'].astype(int)\ntrain[\'P28\'] = train[\'P28\'].astype(int)\ntest[\'P28\']    = test[\'P28\'].astype(int)\ntrain[\'P13\'] = train[\'P13\'].astype(int)\ntest[\'P13\']    = test[\'P13\'].astype(int)\ntrain[\'P2\'] = train[\'P2\'].astype(int)\ntest[\'P2\']    = test[\'P2\'].astype(int)\ntrain[\'P3\'] = train[\'P3\'].astype(int)\ntest[\'P3\']    = test[\'P3\'].astype(int)\ntrain[\'P4\'] = train[\'P4\'].astype(int)\ntest[\'P4\']    = test[\'P4\'].astype(int)\''}, {'role': 'assistant', 'content': "['data_preprocessing']"}]