text: def erathos(n):
      '''
      Create an Erathostenes sieve for prime numbers
      '''
      l = list(range(n))
      l[1] = 0
      sqrt = int(round(n**0.5))
      for i in range(2, sqrt+1):
          if l[i]:
              l[i*i: n: i] = [0] * len(range(i*i, n, i))
      return filter(None, l)
  
  
  def sum_primes(n):
      return sum(erathos(n))
  