def update_defaults(self, prop_value_dict):
        """
        Updates the value of one or more visual properties.

        :param prop_value_dict: Dictionary containing, for each visual property,
            the new value to use.
        """

        body = []
        for key in prop_value_dict:
            entry = {
                'visualProperty': key,
                'value': prop_value_dict[key]
            }
            body.append(entry)

        url = self.__url + 'defaults'
        requests.put(url, data=json.dumps(body), headers=HEADERS)
Updates the value of one or more visual properties.

        :param prop_value_dict: Dictionary containing, for each visual property,
            the new value to use.