[{'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:#Encoding cyclical features\ndata['Month_sin'] = data['Month'].apply(lambda x: np.sin((2*np.pi*x)/12))\ndata['Month_cos'] = data['Month'].apply(lambda x: np.cos((2*np.pi*x)/12))\ndata['Hour_sin'] = data['Hour'].apply(lambda x: np.sin((2*np.pi*(x+1))/24))\ndata['Hour_cos'] = data['Hour'].apply(lambda x: np.cos((2*np.pi*(x+1))/24))\ndata['DayOfWeek_sin'] = data['Day of Week'].apply(lambda x: np.sin((2*np.pi*(x+1))/7))\ndata['DayOfWeek_cos'] = data['Day of Week'].apply(lambda x: np.cos((2*np.pi*(x+1))/7))"}, {'role': 'assistant', 'content': 'data_preprocessing'}]