Django ORM, how to use values() and still work with choicefield?

I am using django v1.10.2

I am trying to create dynamic reports whereby I store fields and conditions and the main ORM model information into database.

My code for the generation of the dynamic report is

class_object = class_for_name("app.models", main_model_name)

results = (class_object.objects.filter(**conditions_dict)
                               .values(*display_columns)
                               .order_by(*sort_columns)
                               [:50])

So main_model_name can be anything.
This works great except that sometimes associated models of the main_model have choicefield.

So for one of the reports main_model is Pallet.
Pallet has many PalletMovement.
My display columns are :serial_number, created_at, pallet_movement__location

The first two columns are fields that belong to Pallet model. The last one is from PalletMovement

What happens is that PalletMovement model looks like this:

class PalletMovement(models.Model):
    pallet = models.ForeignKey(Pallet, related_name='pallet_movements',
                               verbose_name=_('Pallet'))
    WAREHOUSE_CHOICES = (
        ('AB', 'AB-Delaware'),
        ('CD', 'CD-Delaware'),
    )
    location = models.CharField(choices=WAREHOUSE_CHOICES,
                                max_length=2,
                                default='AB',
                                verbose_name=_('Warehouse Location'))

Since the queryset will return me the raw values, how can I make use of the choicefield in PalletMovement model to ensure that the pallet_movement__location gives me the display of AB-Delaware or CD-Delaware?

Bear in mind that the main_model can be anything depending on what I store in the database.

Presumably, I can store more information in the database to help me do the filtering and presentation of data even better.