Return UTC datetime from timestamp in config file.

        :param section: Config section
        :param option: Config option
        :param value: Datetime value to set
        :type value: :class:`datetime.datetime`

def set_datetime(self, section, option, value):
        """
        Return UTC datetime from timestamp in config file.

        :param section: Config section
        :param option: Config option
        :param value: Datetime value to set
        :type value: :class:`datetime.datetime`
        """
        self[section][option] = value.strftime(self.DATETIME_FMT)