Coding help required in Python using VS Code

[PyDev]

How about programming it this way?

#import GUI - easyGUI (download with pip required, command - "pip install easygui")
from easygui import *

#Creating dict item: cost
items={'A': 20, 'B': 55, 'C': 10, 'D': 5}

#Creating list, where will be items selected by user
items_selected=[]

#This code will create the pop-up window, which will get the information: Would user like to add item A, next, save the answer in variable, and finally, 
#add the item if user want to add it
x=ynbox('Do you want to add item A (cost: 20$)?', 'App')
if x:
    items_selected.append('A')

#The same with other items
x=ynbox('Do you want to add item B (cost: 55$)?', 'App')
if x:
    items_selected.append('B')

x=ynbox('Do you want to add item C (cost: 10$)?', 'App')
if x:
    items_selected.append('C')

x=ynbox('Do you want to add item D (cost: 5$)?', 'App')
if x:
    items_selected.append('D')

#Variable "result" will contain totall cost of all items selected by user
result=0

#This fragment will add cost of items selected by user to variable "result"
for a in items_selected:
    result+=items[a]

#This window will display total cost of the items selected by user
msgbox('Total cost of item added: '+str(result), 'App')

#Koniec

This way of programming it is shortest, but displays one window to choice items, and the second to display results, not 4 to choice items and the 5th to display results, as the previous app.

#import GUI - easyGUI (download with pip required, command - "pip install easygui")
from easygui import *

#Creating dict item: cost
items={'A': 20, 'B': 55, 'C': 10, 'D': 5}

#This window will be multi choice box - you can select one, two, three or four items at once
choices=multichoicebox('What items would you like to add?\n Items cost:\nA - 20$\nB - 55$\nC - 10$\nD - 5$', 'App', ['A', 'B', 'C',  'D'])

#This fragment will add cost of items selected by user to variable "result"
for a in choices:
    result+=items[a]

#This window will display total cost of the items selected by user
msgbox('Total cost of item added: '+str(result), 'App')

Check both programs. I hope I helped. If you have some questions, write to me.