[Fixed]-Django: defining a generic manager in an Abstract model

I don’t understand the way you write your manager. If the NATURAL_KEY is an attribute of each model, I would write:

class NexchangeManager(models.Manager):
    def get_by_natural_key(self, param):
        qs = self.get_queryset()
        if param == "*":
           return qs.all()
        lookup = {qs.model.NATURAL_KEY: param}
        return qs.filter(**lookup)

Note: this answer is based on albars answer, but improved for allowing pk params.

manager:

class NexchangeManager(models.Manager):
    def get_by_natural_key(self, param):
        qs = self.get_queryset()
        if param == "*":
            return self.all()
        lookup = {qs.model.NATURAL_KEY: param}
        return self.get(**lookup)

Generic Model class:

class NexchangeModel(models.Model):
    class Meta:
        abstract = True
    objects = NexchangeManager()