code it in python please.

The Fibonacci numbers are the sequence of numbers F1,F2,F3, where: - F1=F2=1 - Fn=Fn1+Fn2 The Fibonacci numbers for n=1,2,,8 are 1,1,2,3,5,8,13,21. Use the function design recipe to develop a function named fib. The function header (with missing type annotations) is: fib(n). Parameter n is a positive integer. The function returns the n th Fibonacci number. For example, fib(1) returns 1 and fib(6) returns 8 . Your function definition must have type annotations and a complete docstring. Your function must have exactly one loop. Type the function definition below the comment, \# Exercise 7. Use the Python shell to test fib