Vending machine help

[wiggles]

Sure, so I can get my code to run for the project up until it asks to insert a coin (lines 33 - 36). I was trying to pull the method that was Vending_Machine.insert_coin in the Vending Machine class. I think it pulls correctly, as I get the right String output. However, I can't seem to get it to follow on with the rest of the user_input class? It just seems to stop?
Thanks Wiggles

#creating a dictionary to outline all the drinks in the machine and their price
class Vending_Machine: 
    aussie_coins = (0.05, 0.10, 0.20, 0.50, 1.00, 2.00)
    items = ['Tea','Coffee', 'Coke', 'Orange Juice']
    item_price = [0.50, 1.00, 1.50, 1.00]
    item_code = ['1', '2', '3', '4']
    
    def __init__(self): #define total in vending machine. 
        self.total = 0.00
        
    def insert_coin(self,coin):
        if float(coin) not in (self.aussie_coins):
            print ('The Vending Machine accepts only: {}. ' .format(self.aussie_coins), end = '')
        else:
            self.total += coin
            print ('Currently there is a total of ${:.2f} in machine' .format(self.total))
            
class interface(Vending_Machine):            
    def menu(self):
        print("##################################")
        print(" Welcome to Tom's Vending Machine ")
        print("All items below are readily available")
        print(Vending_Machine.item_code[0], Vending_Machine.items[0], "${: .2f}".format(Vending_Machine.item_price[0])) #
        print(Vending_Machine.item_code[1], Vending_Machine.items[1], "${: .2f}".format(Vending_Machine.item_price[1]))
        print(Vending_Machine.item_code[2], Vending_Machine.items[2], "${: .2f}".format(Vending_Machine.item_price[2]))
        print(Vending_Machine.item_code[3], Vending_Machine.items[3], "${: .2f}".format(Vending_Machine.item_price[3]))
        print("##################################")
        
class user_input(interface):
        def choice (self):
            choice = input("Please enter the item code of an item you would like to purchase: ")
            if choice == Vending_Machine.item_code[0]:
                print ("You have selected {} - the price is ${: .2f}. Currently you have a total of ${: .2f} in the machine." .format(Vending_Machine.items[0], Vending_Machine.item_price[0], self.total))
                if self.total < Vending_Machine.item_price[0]: 
                    coins = float(input("Insert a coin into the vending machine: "))
                    Vending_Machine.insert_coin(self,coins)
                elif self.total > Vending_Machine.item_price[0]:
                    self.total -= Vending_Machine.item_price[0]
                    print('Please take your {}. Total of {: .2f} in the machine' .format(Vending_Machine.items[0],self.total))
                elif self.total == Vending_Machine.item_price[0]:
                    self.total -= Vending_Machine.item_price[0]
                    print('Please take your {}. Thanks, have a nice day!'.format(Vending_Machine.items[0]))
                
            elif choice == Vending_Machine.item_code[1]:
                print ("You have selected {} - the price is ${: .2f}. Currently you have a total of ${: .2f} in the machine." .format(Vending_Machine.items[1], Vending_Machine.item_price[1], self.total))
                if self.total < Vending_Machine.item_price[1]: 
                    insert_coin(input("Insert a coin into the vending machine: "))
                elif self.total > Vending_Machine.item_price[1]:
                    self.total -= Vending_Machine.item_price[1]
                    print('Please take your {}. Total of {: .2f} in the machine' .format(Vending_Machine.items[1],self.total))
                elif self.total == Vending_Machine.item_price[1]:
                    self.total -= Vending_Machine.item_price[1]
                    print('Please take your {}. Thanks, have a nice day!'.format(Vending_Machine.items[1]))
        
            elif choice == Vending_Machine.item_code[2]:
                print ("You have selected {} - the price is ${: .2f}. Currently you have a total of ${: .2f} in the machine." .format(Vending_Machine.items[2], Vending_Machine.item_price[2], self.total))
                if self.total < Vending_Machine.item_price[2]: 
                    insert_coin(input("Insert a coin into the vending machine: "))
                elif self.total > Vending_Machine.item_price[2]:
                    self.total -= Vending_Machine.item_price[2]
                    print('Please take your {}. Total of {: .2f} in the machine' .format(Vending_Machine.items[2],self.total))
                elif self.total == Vending_Machine.item_price[2]:
                    self.total -= Vending_Machine.item_price[2]
                    print('Please take your {}. Thanks, have a nice day!'.format(Vending_Machine.items[2]))
            
            elif choice == Vending_Machine.item_code[3]:
                print ("You have selected {} - the price is ${: .2f}. Currently you have a total of ${: .2f} in the machine." .format(Vending_Machine.items[3], Vending_Machine.item_price[3], self.total))
                if self.total < Vending_Machine.item_price[3]: #if not the price of tea then.. 
                    insert_coin(input("Insert a coin into the vending machine: "))
                elif self.total > Vending_Machine.item_price[3]:
                    self.total -= Vending_Machine.item_price[3]
                    print('Please take your {}. Total of {: .2f} in the machine' .format(Vending_Machine.items[3],self.total))
                elif self.total == Vending_Machine.item_price[3]:
                    self.total -= Vending_Machine.item_price[3]
                    print('Please take your {}. Thanks, have a nice day!'.format(Vending_Machine.items[3]))
            
                elif choice not in item_code:
                    print("Sorry we do not have item number {} available. Please try again" .format(choice))        
                    


            
vm = Vending_Machine()
i1 = interface()
u1 = user_input()

i1.menu()
u1.choice()