[{'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:# perform LabelEncoder with categorical data (categorical_cols)\nencodering = LabelEncoder()\n\nencod_train_data = train_data.copy()\nencod_test_data = test_data.copy()\nfor col in categorical_cols:\n    encod_train_data[col] = encodering.fit_transform(train_data[col])\n    encod_test_data[col] = encodering.fit_transform(test_data[col])'}, {'role': 'assistant', 'content': 'modelling'}]