finding all prime numbers till a number in python best optimization

# Python Program to find prime numbers in a range 
import time 
def is_prime(n): 
    if n <= 1: 
        return False
    for i in range(2,n): 
        if n % i == 0: 
            return False
    return True
  
# Driver function 
t0 = time.time() 
c = 0 #for counting 
  
for n in range(1,100000): 
    x = is_prime(n) 
    c += x 
print("Total prime numbers in range :", c) 
  
t1 = time.time() 
print("Time required :", t1 - t0)