#!/usr/bin/env python # -*- coding: utf-8 -*- class Data(object): products = { 'milk': {'price': 1.50, 'quantity': 10}, 'eggs': {'price': 0.20, 'quantity': 100}, 'cheese': {'price': 2.00, 'quantity': 10} } class BusinessLogic(object): def __init__(self): self.data = Data() def product_list(self): return self.data.products.keys() def product_information(self, product): return self.data.products.get(product, None) class Ui(object): def __init__(self): self.business_logic = BusinessLogic() def get_product_list(self): print('PRODUCT LIST:') for product in self.business_logic.product_list(): print(product) print('') def get_product_information(self, product): product_info = self.business_logic.product_information(product) if product_info: print('PRODUCT INFORMATION:') print('Name: {0}, Price: {1:.2f}, Quantity: {2:}'.format( product.title(), product_info.get('price', 0), product_info.get('quantity', 0))) else: print('That product "{0}" does not exist in the records'.format( product)) def main(): ui = Ui() ui.get_product_list() ui.get_product_information('cheese') ui.get_product_information('eggs') ui.get_product_information('milk') ui.get_product_information('arepas') if __name__ == '__main__': main() ### OUTPUT ### # PRODUCT LIST: # eggs # milk # cheese # # PRODUCT INFORMATION: # Name: Cheese, Price: 2.00, Quantity: 10 # PRODUCT INFORMATION: # Name: Eggs, Price: 0.20, Quantity: 100 # PRODUCT INFORMATION: # Name: Milk, Price: 1.50, Quantity: 10 # That product "arepas" does not exist in the records