def getItem(self, itemId):
        """gets the refernce to the Items class which manages content on a
        given AGOL or Portal site.
        """
        url = "%s/items/%s" % (self.root, itemId)
        return Item(url=url,
                    securityHandler=self._securityHandler,
                    proxy_url=self._proxy_url,
                    proxy_port=self._proxy_port)
gets the refernce to the Items class which manages content on a
        given AGOL or Portal site.