Write a password cracker program for the passwords created according to the policy outlined in assignment 15 (exactly 8 characters: 5 letters and 3 digits). You are to write a function that takes one parameter that is a hash of a password and should return a possible password (a string) that has the same hash. Use python secure hash function sha1 from hashlib module. Hint: brute force method will be more than adequate to the task.