[{'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:def loadData(df, test = None):\n    \n    dt = pd.to_datetime(df.datetime).dt\n    df["Year"] = dt.year\n    df["Month"] = dt.month\n    df["Day"] = dt.day\n    df["Hour"] = dt.hour\n    \n    df.drop("datetime", axis = 1, inplace = True)\n    if not test:\n        df.drop("casual", axis = 1, inplace = True)\n        df.drop("registered", axis = 1, inplace = True)\n    if test:\n        y = None\n    else:\n        y = df["count"]\n        df.drop("count", axis = 1, inplace = True)\n        \n    X = df\n    \n    return X, y\n        \n        '}, {'role': 'assistant', 'content': 'data_preprocessing'}]