Worst dedupe function ever, but example of manual migration runnnig a function

gistfile1.txt

# -*- coding: utf-8 -*-
from __future__ import unicode_literals

from django.db import migrations


def dedupe_codes(apps, schema_editor):
    codes = []
    count = 0
    measures = apps.get_model('measures', 'Measure')
    for measure in measures.objects.all():
        if measure.code in codes:
            count += 1
            measure.code = "deduped-{}-{}".format(count, measure.code)
            measure.save()
        codes.append(measure.code)


class Migration(migrations.Migration):

    dependencies = [
        ('measures', '0025_measure_aggregation'),
    ]

    operations = [
        migrations.RunPython(dedupe_codes),
    ]