def _yield_week_day(self, enumeration=False):
        """A helper function to reduce the number of nested loops.
        
        Parameters
        ----------
        enumeration
            Whether or not to wrap the days in enumerate().
            
    
        Yields
        -------
        tuple
            A tuple with (week, day_index, day) or (week, day),
            depending on 'enumeration' parameter.

        """
        if enumeration:
            # Iterate over all weeks
            for week in range(1, self.duration + 1):
                # Iterate over all days
                for day_index, day in enumerate(self.days):
                    yield (week, day_index, day)
        else:
            # Iterate over all weeks
            for week in range(1, self.duration + 1):
                # Iterate over all days
                for day in self.days:
                    yield (week, day)