Find Primes Number within a certain limit using the sieve of eratosthenes

findPrimes.py

import sys
import math


def find_primes(max_number):
    is_composite = range(0, max_number + 1)

    for i in range(4, max_number, 2):
        is_composite[i] = True

    next_prime = 3
    stop_at = math.sqrt(max_number)
    
    while next_prime <= stop_at:
        for i in range(next_prime * 2, max_number, next_prime):
            is_composite[i] = True
    
        next_prime = next_prime + 2

        while next_prime <= max_number and is_composite[next_prime] == True:
           next_prime = next_prime + 2
           
    primes = []
    for i in range(2, max_number):
        if is_composite[i] != True:
            primes.append(i)
            
    print(primes)
    return primes


def main():
    find_primes(int(sys.argv[1]))


if __name__ == '__main__':
    main()