'Get the poc code by ssvid
param: ssvid
a ssvid, a seebug poc.
ex: https://www.seebug.org/vuldb/ssvid-89715, 89715 is a ssvid.'

def poc_code(self, ssvid):

    code = None
    detail = self.poc_detail(ssvid)
    if (detail and ('code' in detail)):
        code = detail.get('code')
    return code
