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Calendar.py

#I programmed this to make a Calender project
from time import strftime
USER_FIRST_NAME = "User"
calender = {}
def welcome():
  print "Welcome to your Calender" + USER_FIRST_NAME + "."
  print "Calender starting..." 
  sleep(1)
  print "Today's date: " + strftime("%A %B %d, %XY")
  sleep(1)
  print "Current time: " + strftime("%H, %M, %S")
  sleep(1)
def start_calender():
  welcome
  start = True
  while start:
    user_choice = raw_input("A to Add, U to Update, V to view, D to Delete, X to Exit")
    user_choice = user_choice.upper()
    if user_choice == 'V':
      if len(calender.keys()) < 1:
        print "Calendar empty."
        	else:
          	print calender
   	elif user_choice == 'U':
      date = raw_input("What date?: ")
      update = raw_input("Enter the update: ":
      calender[date] = update
      print "Update successful"
      print calender
      event = raw_input("Enter event: ")
      date = raw_input("Enter date (MM/DD/YYYY): ")
      if(len(date) > 10 or int(date[6:]) < int(strftime ("%Y"))):
      print "Invalid date was entered"
      try_again = raw_input("Try again? Y for Yes, N for No: ")
      try_again = try_again.upper()
      if  try_again == 'Y'
      	continue
        	else:
          	start = False
            	else:
              	calendar[date] = event
                print "Update sucess"
                  print calender
    elif user_choice == 'D':
    	if len(calender.keys()) < 1:
      	print "Calender is empty"
        	else:
          event = raw_input("What event?: ")
          	for date in calender.keys():
            	if event == calender[date]:
              	del (calender[date]
                	print "Event succesfully deleted"
                  	print calendar
                    	else:
                    		print "Invalid event was specified"
   	elif user_choice == 'X':
    	start = False 
    		else:
    			print "Invalid command"
          	break
                            
    
  start_calender()