use cached_property for unit_price and line_total
use cached_property for unit_price and line_total

nimbis/django-shop,jrief/django-shop,nimbis/django-shop,awesto/django-shop,divio/django-shop,khchine5/django-shop,jrief/django-shop,divio/django-shop,jrief/django-shop,khchine5/django-shop,khchine5/django-shop,awesto/django-shop,awesto/django-shop,jrief/django-shop,nimbis/django-shop,nimbis/django-shop,khchine5/django-shop,divio/django-shop