[{'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 gradient_descent(X, y, iter_nums = 100, alpha = 0.01):\ntheta = np.random.rand(4,)\nm = X.shape[0]\ncost_df = pd.DataFrame(columns=['Cost'])\nfor i in range(iter_nums):\ntheta = theta - (alpha / m) * np.dot(np.transpose(X), (h(theta, X) - y))\ncost = cost_function(theta, X, y)\ncost_df.loc[i] = [cost]\nreturn theta, cost_df"}, {'role': 'assistant', 'content': 'modelling'}]