shopping list question

import os

shopping_list=[]
def show():
  clear() 
  index= 1
  print("heres your list")
  for item in shopping_list:
    print("{},{}".format(index,item))
    index+=1



def clear():
  os.system("cls" if os.name=="nt" else "clear")  

def help():
    clear()
    print("what would you like to pick up")
    print("enter 'DONE' to stop adding items")
    print("Enter 'HELP' to see help")
    print("Enter 'SHOW' to see your list")

def addtolist(item):
  show()
  if len(shopping_list):
    posistion = input("where should I add {}?\n"
                      "Press Enter to add to the end of the list\n"
                      "> ".format(item))
  else:
        posistion = 0

  try:
    posistion = abs(int(posistion))
  except ValueError:
    position = None
  if posistion is not None:
    shopping_list.insert(posistion-1,item)
  else: 
    shopping_list.append(item)
    show_list()


help()
while True:
  item = input("Enter an item you would like: ")
  if item.upper =='DONE' or item.upper()=='QUIT':
      break
  elif item.upper == 'HELP':
      help()
      continue
  elif item.upper =='SHOW':
      show()
      continue
  else:    
      addtolist(item)


print("You have " + ", ".join(shopping_list)+" on the list")```