write a python code

In Prac 3 you wrote a program to calculate a dog's age in dog years. Rewrite this program using a function for the conversion. Write a main function that repeatedly asks the user for an age in human years, then displays it in dog years until the user enters a negative number. Don't do any error checking on this age. Here's the calculation part already: if human_years 2: dog_years - human_years - 10.5 else: dog_years = 21 + 4 (human_years - 2)