[{'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:# Open\nfig, (axis1) = plt.subplots(1,1,figsize=(15,4))\nsns.countplot(x=\'Open\',hue=\'DayOfWeek\', data=rossmann_df,palette="husl", ax=axis1)\n\n# fill NaN values in test_df with Open=1 if DayOfWeek != 7\ntest_df["Open"][test_df["Open"] != test_df["Open"]] = (test_df["DayOfWeek"] != 7).astype(int)\n\n# Drop Open column\n# rossmann_df.drop("Open", axis=1, inplace=True)\n# test_df.drop("Open", axis=1, inplace=True)\''}, {'role': 'assistant', 'content': 'data_preprocessing'}]