import random

def get_desktop_uagent(uagent=None):

    desktop_uagents = {
        "MSIE9.0"  : "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)",
        "MSIE8.0"  : "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0)",
        "MSIE7.0"  : "Mozilla/5.0 (Windows; U; MSIE 7.0; Windows NT 6.0; en-US)",
        "MSIE6.0"  : "Mozilla/5.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)",
        "Chrome32" : "Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1667.0 Safari/537.36",
        "Chrome31" : "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.16 Safari/537.36",
        "Firefox25": "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20100101 Firefox/25.0",
        "Firefox24": "Mozilla/5.0 (Windows NT 6.0; WOW64; rv:24.0) Gecko/20100101 Firefox/24.0,",
        "Safari5.1": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_6_8) AppleWebKit/537.13+ (KHTML, like Gecko) Version/5.1.7 Safari/534.57.2",
        "Safari5.0": "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.18.1 (KHTML, like Gecko) Version/5.0 Safari/533.16"
    }

    if not uagent: 
        return desktop_uagents[random.choice(desktop_uagents.keys())]
    elif uagent:
        return desktop_uagents[uagent]