TPT Save backup

import urllib, urllib2
import re
import sys
import json

def FatalError(message):
    print(message)
    exit(1)

def GetPage(url, cookies = None, headers = None, removeTags = False):
    if cookies:
        req = urllib2.Request(url, urllib.urlencode(headers) if headers else None, {'Cookie':cookies})
    else:
        req = urllib2.Request(url)
    page = urllib2.urlopen(req, timeout=10).read()
    if removeTags:
        return re.sub("<.*?>", "", page)
    return page

def GetSessionInfo():
    try:
        powderpref = open("powder.pref", "r")
        prefs = json.loads(powderpref.read())
        powderpref.close()
        return "UserRemember=Yes; UserID={0}; UserKey={1}".format(prefs["User"]["ID"],prefs["User"]["SessionID"])
    except:
        return None

def GetUsername():
    try:
        powderpref = open("powder.pref", "r")
        prefs = json.loads(powderpref.read())
        powderpref.close()
        return prefs["User"]["Username"]
    except:
        return None

def GetMaxPage(page):
    pagelinks = []
    pagelinks.extend(re.findall("/User/Saves.html\?ID=[0-9]*&amp;PageNum=([0-9]*)", page))
    if pagelinks:
        return int(max(pagelinks))
    else:
        return 0

if __name__ == "__main__":
    username = None
    start = 0
    end = -1
    for arg in sys.argv[1:]:
        (argname, argvalue) = arg.split("=")
        if argname == "--username":
            username = argvalue
        elif argname == "--pages":
            (start,end) = map(int, argvalue.split(","))
        else:
            FatalError("Valid arguments: --username=<name>, --pages=<start>,<end>")
    if not username:
        username = GetUsername()
        if not username:
            FatalError("Could not get username from powder.pref, use the --username argument")
    print(username)
    if start < 0 or end < 0:
        link = "http://powdertoy.co.uk/User/Saves.html?Name=%s" % username
        page = GetPage(link, GetSessionInfo())
        if page:
            end = GetMaxPage(page)
        else:
            FatalError("Could not get number of pages to fetch saves from, use the --pages argument")
    print(start,end)

    matches = []
    for i in range(start, end):
        link = "http://powdertoy.co.uk/User/Saves.html?Name=%s&PageNum=%s" % (username, i)
        page = GetPage(link, GetSessionInfo())
        matches.extend(re.findall("http://static.powdertoy.co.uk/([0-9]*)_small.png", page))
    print(matches)
    for i in matches:
        save = GetPage("http://static.powdertoy.co.uk/%s.cps" % i)
        f = open(i+".cps", "w")
        f.write(save)
        f.close()