# Your code goes here
cal = calendar.load_calendar()
print('calendar loaded')

while (True):
   user_input = input('>> ')
   parse = calendar.parse_command(user_input)

   if user_input == 'help':
         print(calendar.command_help())
   elif parse[0] == 'help':
         print(calendar.command_help())
   elif 'add' in user_input:
   if 'add DATE START_TIME END_TIME DETAILS' in parse:
   print("Command 'add' not used properly. Check help for more information.")
   elif 'not a valid calendar date' in parse:
   print("%s is not a date in the calendar" %(parse[1]))
   elif 'not a valid time' in parse:
   print('Not a valid time.')
   else:
   parse.remove('add')
   parse.append(cal)
   calendar.command_add(*parse)
   print('added')
   elif 'show' in user_input:
   if 'error' in parse:
   print("Command 'show' not used properly. Check help for more information.")
   else:
   print(calendar.command_show(cal))
   elif 'delete' in user_input:
   if 'delete DATE START_TIME' in parse:
   print("Command 'delete' not used properly. Check help for more information.")

Problem 1 (Preserving Invariants). For each of the following loop i...