[{'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:(X_train, y_train), (X_test, y_test) = mnist.load_data()\nprint('X_train original shape:', X_train.shape)\ninput_shape = (nb_time_steps, dim_input_vector)\nX_train = X_train.astype('float32') / 255.\nX_test = X_test.astype('float32') / 255.\nY_train = np_utils.to_categorical(y_train, nb_classes)\nY_test = np_utils.to_categorical(y_test, nb_classes)\nprint('X_train shape:', X_train.shape)\nprint(X_train.shape[0], 'train samples')\nprint(X_test.shape[0], 'test samples')"}, {'role': 'assistant', 'content': 'load_data'}]