def perform_check(self, packages):
        data = json.dumps({'installed_packages': packages}).encode('utf-8')
        req = Request(self.URL, data, {'Content-Type': 'application/json'})

        try:
            res = urlopen(req)
        except HTTPError as e:
            sublime.error_message(e.code % 'Could not perform check. Server returned %s')
            return
        except URLError as e:
            sublime.error_message('Could not connect to http://www.caniswitchtosublimetext3.com')
            return

        location = res.info().get('Location')
        webbrowser.open(location)
dataset/ETHPy150Open SublimeGit/CanISwitchToSublimeText3/CanISwitch.py/CanSwitchCommand.perform_check/swapped operands of `%`