Django ORM function to sum absolute values.

django_absolute_sum.py

from django.db.models import Sum


class AbsoluteSum(Sum):
    name = 'AbsoluteSum'
    template = '%(function)s(%(absolute)s(%(expressions)s))'

    def __init__(self, expression, **extra):
        super(AbsoluteSum, self).__init__(
            expression, absolute='ABS ', output_field=IntegerField(), **extra)

    def __repr__(self):
        return "SUM(ABS(%s))".format(
            self.arg_joiner.join(str(arg) for arg in self.source_expressions)
        )