code: def every(self, **kwargs):
          
          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
docs: 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