[{'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:# Preprocessing for linear regression\n\nfrom sklearn.preprocessing import OneHotEncoder\nfrom sklearn.model_selection import train_test_split\nfrom sklearn.preprocessing import MinMaxScaler\n\nscaler = MinMaxScaler()\nX_train_norm = scaler.fit_transform(X_train)\nX_test_norm = scaler.transform(X_test)\n\none_hot = OneHotEncoder(categorical_features = [0, 1, 2, 3]) #season, holiday, workingday and weather\nX_train_norm = one_hot.fit_transform(X_train_norm)\nX_test_norm = one_hot.transform(X_test_norm)'}, {'role': 'assistant', 'content': 'data_preprocessing'}]