Design black box test cases using equivalent partitions to test a code that takes the amount of money a customer purchased from a store and gives him a coupon accordingly. If the purchase amount is equal or less than AED $1000$ the customer gets AED $20$ coupon; otherwise, the customer gets AED $50$ coupon.

$5$ marks$)$: Using a language of your choice, write the code mentioned in part a and draw the corresponding control flow raph.

marks$]$: Determine the cyclomatic complexity of that code in part b$,$ and justify your answer.