how to use while in the function if result = 1 then exit

i start learning python i write this code to check if the number is even or odd , if the number is even then take that number and / 2 if the number is odd then do : 3 * number + 1

i dont know where to put while

my code:

def collatz(number):

if number % 2 == 0:
    return number / 2
else:
    return 3 * number + 1    
print("enter the number ")
qassam = int(input())
print(collatz(qassam))

i want to exit when the result of any if conditions = 1 how to do that ?