fix creation of consuption line

from trytond.model import ModelView, fields, Workflow

from trytond.pool import PoolMeta

from trytond.pool import PoolMeta,Pool

from trytond.pyson import Eval

__all__ = ['Subscription']

                if (line.next_consumption_date is None

                        and not line.consumed):

                    if subscription.include:

                        subscription.next_invoice_date = (subscription.invoice_start_date or subscription.start_date)

                        line.next_consumption_date = (subscription.invoice_start_date or subscription.start_date)

                    else:

                        line.next_consumption_date = (line.compute_next_consumption_date())

            lines.extend(subscription.lines)