def every(self, **kwargs):
        """
        Specify the interval at which you want the job run.  Takes exactly one keyword argument.
        That argument must be one named one of [second, minute, hour, day, week, month, year] or
        their plural equivalents.

        :param kwargs: Exactly one keyword argument
        :return: self
        """
        if len(kwargs) != 1:
            raise ValueError('.every() method must be called with exactly one keyword argument')

        self._every_kwargs = self._clean_kwargs(kwargs)

        return self
Specify the interval at which you want the job run.  Takes exactly one keyword argument.
        That argument must be one named one of [second, minute, hour, day, week, month, year] or
        their plural equivalents.

        :param kwargs: Exactly one keyword argument
        :return: self