Can someone help me detect what is wrong with my code

Community
1 
from time import sleep, strftime

from datetime import time

USER_FIRST_NAME = "Teddy"

calendar = {}

def welcome():
  print("Welcome " + USER_FIRST_NAME + "." )
  print("The calendar is ready to use.")
  sleep(1)
  print("Today is: : " + strftime("%A %B %d, %Y")) 
  print("Current time is: " + strftime("%H:%M:%S"))
  sleep(1)
  print("What would you like to do? ")
  
def start_calendar():
  welcome()
  start = True
  while start:
    user_choice = input("1. A -> to Add\n2. U -> to Update\n3. V -> to View\n4. D -> to Delete\n4. X -> to Exit\nChoose an Option: ")
    user_choice = user_choice.upper()
    if user_choice == 'V':
      if len(calendar.keys()) < 1:
        print("Calendar is empty.")
      else:
        print(calendar)
    elif user_choice == 'U':
      date = input("What date? ")
      update = input("Enter the update: ")
      calender[date] = update
      print("The calendar is now updated.")
      print(calendar)
    elif user_choice == 'A':
      event = input("Enter event: ")
      date = input("Enter date (MM/DD/YYYY): ")
      if len(date) > 10 or int(date[6:]) < int(strftime("%Y")):
        print("An invalid Date was entered:")
        try_again = input("Try Again? Y for yes, N for No: ")
        try_again = try_again.upper()
        if try_again == 'Y' or try_again == 'y':
          continue
        else:
          start = False
      else:
        calendar[date] = event
        print("Event was successfully added")
        print(calendar)
    elif user_choice == 'D':
      if len(celendar.keys()) < 1:
        print("The calendar is empty,")
      else:
        event = input("What event? ")
        for date in calendar.keys():
          if event == calendar[date]:
            del calendar[date]
            print("The event was successful deleted. ")
          else:
            print("An invalid date was entered")
    elif user_choice == 'X':
      start = False
    else:
      print("Wrong input")
      
      
start_calendar()
2

whenever i enter a date it keeps saying wrong input…

3

the year needs to be valid (2018 and beyond). The only way i can reproduce the error is by entering 2017 or earlier.

4

Thanks i see whats causing the problem.