[{'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:categorical_features = [\n    'affiliate_channel',\n    'affiliate_provider',\n    'first_affiliate_tracked',\n    'first_browser',\n    'first_device_type',\n    'gender',\n    'language',\n    'signup_app',\n    'signup_method'\n]\n\n# one-hot-encoding\nfor categorical_feature in categorical_features:\n    all_users_dummies = pd.get_dummies(all_users[categorical_feature], prefix=categorical_feature)\n    all_users = all_users.drop([categorical_feature], axis=1)\n    all_users = pd.concat((all_users, all_users_dummies), axis=1)"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]