So, your app is growing nicely, but you find yourself repeating the same field definition in a bunch of models. The models themselves have nothing to do with each other, so an abstract base class isn't a fit, but at various points you want, say, prices to always be the same configuration of DecimalField, or titles to always allow the same size.
So, you could sub-class the fields to produce your own pre-configured fields, but sometimes you want to vary them a little... this price is nullable, that title has help_text, and so on.
Enter the joy of functools.partial
Here's a little sample from a project I'm currently working on:
import functools PriceField = functools.partial(models.DecimalField, decimal_places=2, max_digits=10)
So what have we got here? Now, on my models I can put:
class MyModel(models.Model): price = PriceField() tax = PriceField(null=True, blank=True, help_text='Where applicable.')
So, now my two fields are DecimalFields, with the same digits, etc., but some differences.
How about an even more common case:
from datetime import datetime AutoDateTimeField = functools.partial(models.DateTimeField, default=datetime.now)