[{'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:df_train = df_train.drop(['Soil_Type8', 'Soil_Type25'], axis=1)\ndf_test = df_test.drop(['Soil_Type8', 'Soil_Type25'], axis=1)\ndf_train1 = df_train # To be used for algos like SVM where we need normalization and StandardScaler\ndf_test1 = df_test # To be used under normalization and StandardScaler"}, {'role': 'assistant', 'content': 'data_preprocessing'}]