Jumped the gun--don't want a custom field.

savepointradio/radio/fields.py

@@ -1,35 +0,0 @@
-import re
-from unicodedata import normalize
-
-from django.db import models
-
-
-class NaturalSortField(models.CharField):
-    """
-    A custom model field specifically for storing a normalized unicode string,
-    with removed starting articles, for use in natural sorting.
-
-    Code is a modified version of 'django-naturalsortfield' by Nathan Reynolds:
-    https://github.com/nathforge/django-naturalsortfield
-    """
-    def __init__(self, for_field, **kwargs):
-        self.for_field = for_field
-        kwargs.setdefault('db_index', True)
-        kwargs.setdefault('editable', False)
-        kwargs.setdefault('max_length', 255)
-        super(NaturalSortField, self).__init__(**kwargs)
-
-    def pre_save(self, model_instance, add):
-        return self.naturalize(getattr(model_instance, self.for_field))
-
-    def naturalize(self, string):
-        def naturalize_int_match(match):
-            return '%08d' % (int(match.group(0)),)
-
-        string = normalize('NFKD', string).encode('ascii', 'ignore').decode('ascii')
-        string = string.lower()
-        string = string.strip()
-        string = re.sub(r'^(a|an|the)\s+', '', string)
-        string = re.sub(r'\d+', naturalize_int_match, string)
-
-        return string