Error:"IndentationError: unindent does not match any outer indentation"

def update():
    try:
        lines = open("vbvuln.txt", "r").readlines()
    except(IOError):
         print "[-] Error: Check your phpvuln.txt path and permissions"
         print "[-] Update Failedn"
        sys.exit(1)
    try:

print "[-] Update Failedn"

def update():
    try:
        lines = open("vbvuln.txt", "r").readlines()
    except (IOError):
        print "[-] Error: Check your phpvuln.txt path and permissions"
        print "[-] Update Failedn"
        sys.exit(1)