Source

django-licenses / licenses / fields.py

from django.db.models import ForeignKey
from django.utils.translation import ugettext_lazy as _


class LicenseField(ForeignKey):
	'''
		A ForeignKey field with default value for verbose_name
		and a shortcut for switching blank/null to True.
	'''

	def __init__(self, **kwargs):
		kwargs.setdefault('verbose_name', _('license'))
		if kwargs.pop('required', None) == False:
			kwargs['blank'] = True
			kwargs['null'] = True
		ForeignKey.__init__(self, 'licenses.License', **kwargs)