params.py

import inspect
from urllib.parse import urlparse


class ParameterSet:
    pass


class Field:
    def __init__(self, description, **kwargs):
        self.params = kwargs
        self.params['description'] = description

    def __str__(self):
        return str(self.params)


class URL:
    def __init__(self, url):
        self.original_url = url
        self.url = urlparse(url)


class IntegerField(Field):
    pass


class FloatField(Field):
    pass


class VHF(ParameterSet):
    url = URL('file:///tmp/vhf/')
    threshold_level = FloatField('Threshold level in V when VHF triggers',
                                 min_value=0.0, max_value=600.0, default_value=55.3)
    rms_integator_time = IntegerField('Integrator time in ms',
                                      min_value=0, max_value=20000)


vhf_members = inspect.getmembers(VHF, lambda x: isinstance(x, Field))
print([(name, str(obj)) for name, obj in vhf_members])

• Migrations blog post
  https://realpython.com/blog/python/django-migrations-a-primer/

• Migrations docs
  https://docs.djangoproject.com/en/1.10/topics/migrations/

• Migrations implementation
  https://github.com/django/django/tree/master/django/db/migrations