new_contents: import argparse
  import sys
  
  # Sieve of Eratosthenes
  # Code by David Eppstein, UC Irvine, 28 Feb 2002
  # http://code.activestate.com/recipes/117119/
  
  def gen_primes():
      """ Generate an infinite sequence of prime numbers.
      """
      # Maps composites to primes witnessing their compositeness.
      # This is memory efficient, as the sieve is not "run forward"
      # indefinitely, but only as long as required by the current
      # number being tested.
      #
      D = {}  
  
      # The running integer that's checked for primeness
      q = 2  
  
      while True:
          if q not in D:
              # q is a new prime.
              # Yield it and mark its first multiple that isn't
              # already marked in previous iterations
              # 
              yield q        
              D[q * q] = [q]
          else:
              # q is composite. D[q] is the list of primes that
              # divide it. Since we've reached q, we no longer
              # need it in the map, but we'll mark the next 
              # multiples of its witnesses to prepare for larger
              # numbers
              # 
              for p in D[q]:
                  D.setdefault(p + q, []).append(p)
              del D[q]
          q += 1
  
  if __name__ == "__main__":
      parser = argparse.ArgumentParser(description="Generate prime number array")
      parser.add_argument('n', metavar='N', nargs=1, type=int, help="Limit value")
      group = parser.add_mutually_exclusive_group()
      group.add_argument('--count', action='store_const', const=True,
              default=False, help='limit number of generated prime number (default)')
      group.add_argument('--value', action='store_const', const=True,
              default=False, help='limit max value of generated prime number')
  
      args = parser.parse_args()
      
      if args.value:
          limit = args.n[0]
      else:
          limit = args.n[0]-2
  
      prime = iter(gen_primes())
      sys.stdout.write("{"+str(prime.next()))
      for idx, val in enumerate(prime):
          if args.value and limit < val:
              break
          elif limit < idx:
              break
          sys.stdout.write(", "+str(val))
      print("}")
  
subject: Add array of prime number generator code