Print$\_$stars: Your first exercise is to write a program that asks the user to enter a positive integer number $($we use variable n to denote this number$),$ then prints out n lines of stars: the first line has one star, the second line has two stars, third line three stars, and so on until the n$-$th line, which should have n stars.

is$\_$prime: The second exercise is to write a function to check if a given integer is prime or not. A prime number is defined as a positive integer larger than $1,$ that is only divisible by $1$ and itself, and not divisible by any other integer. For example, $5$ is a prime number because it$$s only divisible by $1$ and $5($itself$)$; $12$ is NOT a prime number because it$$s divisible by $3$ and $4$ in addition to $1$ and itself.

$($python language$)$