[{'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 allvars():\nfor i in data.columns:\nprint(i, data[i].dtype)\nprint(list(data[i].unique()))\nprint()\ndef thesevars(varlist):\nfor i in varlist:\nprint(i, data[i].dtype)\nprint(list(data[i].unique()))\nprint()\ndef checkna():\nnacols = []\nfor i in data.columns:\nif (data[i].isnull().sum() > 0):\nnacols.append(i)\nif(len(nacols) > 0):\nprint(nacols)\nelse:\nprint("No NA values in dataframe")'}, {'role': 'assistant', 'content': 'data_exploration'}]