Set data of type format.

        :arg str type: Data format of the data, like 'text/plain'.

def setData(self, type: str, data: str) -> None:
        """Set data of type format.

        :arg str type: Data format of the data, like 'text/plain'.
        """
        type = normalize_type(type)
        if type in self.__data:
            del self.__data[type]
        self.__data[type] = data