'return an User-Agent at random
:return:'

@property
def user_agent(self):

    ua_list = ['Mozilla/5.0    (Windows    NT    6.1;    WOW64)    AppleWebKit/537.36    (KHTML,    like    Gecko)    Chrome/30.0.1599.101', 'Mozilla/5.0    (Windows    NT    6.1;    WOW64)    AppleWebKit/537.36    (KHTML,    like    Gecko)    Chrome/38.0.2125.122', 'Mozilla/5.0    (Windows    NT    6.1;    WOW64)    AppleWebKit/537.36    (KHTML,    like    Gecko)    Chrome/39.0.2171.71', 'Mozilla/5.0    (Windows    NT    6.1;    WOW64)    AppleWebKit/537.36    (KHTML,    like    Gecko)    Chrome/39.0.2171.95', 'Mozilla/5.0    (Windows    NT    6.1;    WOW64)    AppleWebKit/537.1    (KHTML,    like    Gecko)    Chrome/21.0.1180.71', 'Mozilla/4.0    (compatible;    MSIE    6.0;    Windows    NT    5.1;    SV1;    QQDownload    732;    .NET4.0C;    .NET4.0E)', 'Mozilla/5.0    (Windows    NT    5.1;    U;    en;    rv:1.8.1)    Gecko/20061208    Firefox/2.0.0    Opera    9.50', 'Mozilla/5.0    (Windows    NT    6.1;    WOW64;    rv:34.0)    Gecko/20100101    Firefox/34.0']
    return random.choice(ua_list)
