Write a function named is$\_$prime. It takes a positive integer as a parameter. The function checks if

the positive given number $($greater than zero$)$ is a prime number. The function returns a boolean that is

true if the number is prime.

Use the Python shell to test is$\_$prime.

Examples:

is$\_$prime$(1)$ should return False

is$\_$prime$(7)$ should return True

is$\_$prime$(8)$ should return False