Avoided need to import model fields in models/functions.py.

"""

Classes that represent database functions.

"""

from django.db.models import (

    DateTimeField, Func, IntegerField, Transform, Value,

)

from django.db.models import Func, Transform, Value, fields

class Coalesce(Func):

    lookup_name = 'length'

    def __init__(self, expression, **extra):

        output_field = extra.pop('output_field', IntegerField())

        output_field = extra.pop('output_field', fields.IntegerField())

        super(Length, self).__init__(expression, output_field=output_field, **extra)

    def as_mysql(self, compiler, connection):

    def __init__(self, output_field=None, **extra):

        if output_field is None:

            output_field = DateTimeField()

            output_field = fields.DateTimeField()

        super(Now, self).__init__(output_field=output_field, **extra)

    def as_postgresql(self, compiler, connection):