[{'role': 'system', 'content': "You are an expert in machine learning and your task is to classify the code snippets into categories from the provided list of categories. List of categories: ['helper_functions', 'load_data', 'data_exploration', 'data_preprocessing', 'evaluation', 'modelling', 'prediction', 'result_visualization', 'save_results', 'comment_only']"}, {'role': 'user', 'content': 'Identify to which category the provided code belongs and assign the code snippet to at least 1 but up to 5 categories based on the probabilities, ignore if the probability of the category is negligible. Strictly provide your response as a list. Avoid providing any additional information, commentary, or personal opinions.\\nPython Code:HIV["Increase"] = HIV["HIV2013"] - HIV["HIV2001"]\nHIV.Increase.hist(bins = 20, color = \'c\')\npyplot.xlabel("Change in HIV Prevalance")\npyplot.ylabel("# of Countries")\npyplot.title("Distribution of Change in HIV Prevalances, 2001-2013")\npyplot.axvline(HIV.Increase.mean(), color=\'g\', linestyle=\'dashed\', linewidth=2)'}, {'role': 'assistant', 'content': "['data_exploration']"}]