':return: A tuple with the following information:
* True indicating that the page has CAPTCHAs
* A list with tuples that contain:
* The CAPTCHA image source
* The http responses used to verify that the image was
indeed a CAPTCHA'

def _identify_captchas(self, fuzzable_request):

    found_captcha = False
    captchas = []
    images_1 = self._get_images(fuzzable_request)
    images_2 = self._get_images(fuzzable_request)
    if (len(images_1) == len(images_2)):
        not_in_2 = []
        for (img_src_1, img_hash_1, http_response_1) in images_1:
            for (_, img_hash_2, http_response_2) in images_2:
                if (img_hash_1 == img_hash_2):
                    break
            else:
                not_in_2.append((img_src_1, img_hash_1, [http_response_1, http_response_2]))
        for (img_src, _, http_responses) in not_in_2:
            CaptchaInfo = namedtuple('CaptchaInfo', ['img_src', 'http_responses'])
            img_src = img_src.uri2url()
            if (img_src not in self._captchas_found):
                self._captchas_found.add(img_src)
                found_captcha = True
                captchas.append(CaptchaInfo(img_src, http_responses))
    return (found_captcha, captchas)
