[{'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:#Dataframes etc\nimport pandas as pd\nimport numpy as np\n\n\n#Visualization\nimport matplotlib.pyplot as plt\nimport seaborn as sns\n%matplotlib inline\nfrom matplotlib.colors import ListedColormap\nfrom pylab import rcParams\nrcParams['figure.figsize'] = 10, 8\nsns.set_style('whitegrid')\n\n#Machine learning:\nfrom sklearn import preprocessing\n\n## ML Cross validation and metrics\nfrom sklearn.model_selection import cross_val_score\nfrom sklearn.model_selection import train_test_split\nfrom sklearn import metrics\n\n\n## ML models \nfrom sklearn.linear_model import LogisticRegression\n\n#Natural language processing\nimport nltk\n#nltk.download('punkt')\nfrom nltk.tokenize import word_tokenize, TreebankWordTokenizer\n## to automate the NLP extraction\nfrom sklearn.feature_extraction.text import CountVectorizer\n"}, {'role': 'assistant', 'content': 'helper_functions'}]