Programming: Find prime numbers

Today I bought a new book about programming and algorithms. One of the first examples in the book, which I found very simplistic yet interesting, is the algorithm for finding prime numbers. It goes like this:

1. Let N be the number you want to find if it is prime or not
2. Let X be 2
3. If N equals X, N is a prime. End.
   
4. Divide N by X
5. If the result is an integer, N is not prime. End.
   
6. Add 1 to X.
7. Go to step 3.

In Python, this can be implemented with the following function:
def isitprime(n):
x=2

while True:
if n==x:
return True
elif n%x == 0:
return False
x+=1