[{'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:import numpy as np \nimport pandas as pd \nimport matplotlib.pyplot as plt\nimport seaborn as sns\nfrom sklearn import preprocessing\nimport time\nfrom datetime import datetime\nfrom scipy import integrate, optimize\nimport warnings\nwarnings.filterwarnings('ignore')\n\n# ML libraries\nimport lightgbm as lgb\nimport xgboost as xgb\nfrom xgboost import plot_importance, plot_tree\nfrom sklearn.model_selection import RandomizedSearchCV, GridSearchCV\nfrom sklearn import linear_model\nfrom sklearn.metrics import mean_squared_error\nfrom sklearn.linear_model import Ridge, RidgeCV"}, {'role': 'assistant', 'content': 'helper_functions'}]