Create a program that reads the sales for 12 months from a file and calculates the total yearly sales as well as the average monthly sales. In addition, this program should let the user edit the sales for any mont

import os

def load_file(filename):

   if os.path.isfile(filename) is not True:return None

   sales_dict={}

   with open(filename,'r') as infile:

       for line in infile.readlines():

           line = line.strip().split(',')

           try:

               sales_dict[line[0].lower()] = float(line[1].strip())

           except:

               continue

   return sales_dict

def printMonthlySales(sales_dict):

   month_names=['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct','Nov','Dec']

   for month in month_names:

       print('{0} - {1:>8}'.format(month,sales_dict.get(month.lower(

def printYearlySummary(sales_dict):

   total_sales=0

   for sales in sales_dict.values():

       total_sales+=sales

   print('Yearly Total: ${0}'.format(total_sales))

def edit(sales_dict,filename):

   month_names=['jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec']

   month_name=input('Enter month for which you want to edit the sales amount: ').lower()

   if month_name in month_names:

       sales_amount=float(input('Enter sales amount: '))

       for month,sales in sales_dict.items():

           if month==month_name:

               sales_dict[month_name]=sales_amount

               update_file(sales_dict,filename)

   else:

       print('Invalid month name entered.')

# function to update the file

def update_file(sales_dict, filename):

   with open(filename,'w') as outfile:

       outfile.write('Month,Sales\n')

       month_names=['jan','feb','mar','apr','may','jun','jul','aug','sep','oct','nov','dec']

       for month in month_names:

           outfile.write('{0},{1}\n'.format(month.title(),sales_dict.get(month)))

       print('{} saved successfully'.format(filename))

def main():

   filename='sales.csv' # file name that needs to be read and updated

   sales_dict = load_file(filename)

   if sales_dict is None:

       print('Unable to read data from file: {}'.format(filename))

       return

   print('COMMAND MENU')

   while True:

       print('[1] View Monthly Sales')

       print('[2] View Yearly Summary')

       print('[3] Edit Sales')

       print('[4] Quit')

       choice=input('Enter your choice: ')

       if choice =='1':

           printMonthlySales(sales_dict)

       elif choice=='2':

           printYearlySummary(sales_dict)

       elif choice=='3':

           edit(sales_dict,filename)

       elif choice=='4':break

       else:print('Invalid selection')

main()

Explanation:

answer(true);