class DateMixin

def get_allow_future(self):
    """
    Returns `True` if the view should be allowed to display objects from
    the future.
    """
    return self.allow_future

def get_date_field(self):
    """
    Get the name of the date field to be used to filter by.
    """
    if self.date_field is None:
        raise ImproperlyConfigured(u"%s.date_field is required." % self.__class__.__name__)
    return self.date_field