'Heuristic to infer if the content of <response> has the pattern of a
backdoor response.
:param response: HTTPResponse object
:return: A bool value'

def _match_signature(self, response):

    body_text = response.get_body()
    for (match, _, _, _) in self._signature_re.query(body_text):
        match_string = match.group(0)
        return match_string
    return None
