Sum all primes until a certain number

Soru10.py

def sumPrimesErastothanesWay(n):
	notprime = False
	primemultiples = set()
	sum = 0
	for x in range(2 , n):
		if x in primemultiples:
			notprime = True
		if(notprime != True):
			root = int(math.ceil(math.sqrt(x)))
			for i in range (3, root):
				if x%i == 0 and x != i:
					notprime = True
					break	
			for z in range(2*x , n, x):
				primemultiples.add(z)
			sum += x
		notprime = False
	return sum