Ok, so this is my first Python code ever. It does okay but the def ask_again function keeps returning an error.

def factorial(n):
      if n <= 0:
            return 0
      elif n == 1:
            return 1
      else:
            fact = 1
            while(n > 1):
                  fact *= n
                  n -= 1
            return fact
def getNumberFromUser():
      num = int(input("Please input whole a number under 11: "))
      if (num <= 10):
            return num
      else:
            print ("Sorry wrong number!")
            return -1
def ask_again():
      cont = ''

      while cont not in ("yes", "no"):

            cont = input("Another one?(yes/no)  ").lower()
            if cont == "yes":
                  return cont

            else:
                  break
#print("You chose",num)

while True:
      result = -1
      while (result < 0):
            result = getNumberFromUser()
      fact = factorial(result)
      print("Factorial of ", result, "is", fact)