[{'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:al_copy = pd.merge(al, tci[['parcel','Date']].set_index('parcel'), how='left',left_on='PROPERTY_NUMBER',right_index=True)\ndf = pd.merge(df, al_copy[['date','PROPERTY_NUMBER']]\\\n.groupby('PROPERTY_NUMBER')\\\n.last()\\\n,how='left', left_on='parcel', right_index=True)\ndf.loc[df.date.isnull(),'date'] = dt.datetime(2006,1,1)\ndf = df.rename(columns = {'date':'al_days'})\ndf['al_days'] = (df.Date-df.al_days).astype(pd.Timedelta).apply(lambda x: x.days)"}, {'role': 'assistant', 'content': "['data_preprocessing']"}]