[{'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:df4["daycas"]="cas0"\ndf4["daycas"].loc[df4["hours"]<=6.5]="cas1"\ndf4["daycas"].loc[(df4["hours"]>6.5) & (df4["hours"]<=7.5)]="cas2"\ndf4["daycas"].loc[(df4["hours"]>7.5) & (df4["hours"]<=8.5)]="cas3"\ndf4["daycas"].loc[(df4["hours"]>8.5) & (df4["hours"]<=9.5)]="cas4"\ndf4["daycas"].loc[(df4["hours"]>9.5) & (df4["hours"]<=10.5)]="cas5"\ndf4["daycas"].loc[(df4["hours"]>10.5) & (df4["hours"]<=19.5)]="cas6"\ndf4["daycas"].loc[(df4["hours"]>19.5) & (df4["hours"]<=21.5)]="cas7"\ndf4["daycas"].loc[df4["hours"]>21.5]="cas8"'}, {'role': 'assistant', 'content': 'data_preprocessing'}]