[{'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:t_copy = pd.merge(t, tci[['parcel','Date']].set_index('parcel'), how='left',left_on='PROPERTY_NUMBER',right_index=True)\nt_copy = t_copy.loc[(t_copy.mdate < t_copy.Date) & (t_copy.mdate > dt.datetime(2006,1,1))]\ndays_since_transfer = t_copy.groupby('PROPERTY_NUMBER').first()\ndays_since_transfer['t_days'] = (days_since_transfer.Date - days_since_transfer.mdate).astype(pd.Timedelta).apply(lambda x: x.days)\ndf = pd.merge(df, days_since_transfer[['t_days']], left_on='parcel', right_index=True,how='left')\ndf.loc[df.t_days.isnull(),'t_days'] = max(df.loc[df.t_days.notnull(),'t_days'])+1"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]