Django ORM how to Round an Avg result

Question

I have a model in which I use Django ORM to extract Avg of values from the table. I want to Round that Avg value, how do I do this?

See below I am extracting Avg pri

Answer 1

Improving on @mrts answer.

This allows the round function to be parameterised:

class Round(Func):
  function = 'ROUND'
  arity = 2

Book.objects.all().aggregate(Round(Avg('price'), 2))