def save(self, *args, **kwargs):
        super(ColumnMapping, self).save(*args, **kwargs)
        # Because we need to have saved our ColumnMapping in order to have M2M,
        # We must create it before we prune older references.
        self.remove_duplicates(self.column_raw.all())
Overrides default model save to eliminate duplicate mappings.
dataset/ETHPy150Open buildingenergy/buildingenergy-platform/seed/models.py/ColumnMapping.save