Given the following recursive function write
down the base case conditions such that this function determines if
an integer X is prime or not.
Where X is the number to check whether it is prime or not. Y is a divisor
which is a number below X, when calling the function initially Y equals X-1.
A prime number is divisible evenly only by itself and 1. The recursive
function takes a number and a divisor.
We check to see if the number is prime by dividing it by the divisor.
If it evenly divides then the number is not prime, and we return false.
If the number does not evenly divide then we reduce the divisor by 1
and recurse a level deeper.