If I prompt it, it actually comes up with a decent function:

  def is_prime(element):
    """Returns whether a number is prime."""
    if element < 2:
      return False
    if element == 2:
      return True
    if element % 2 == 0:
      return False
    for i in range(3, int(math.sqrt(element)) + 1, 2):
      if element % i == 0:
        return False
    return True

Of course, if you ask it to keep generating past that there's the usual slow descent into madness.