clinic/netforce_clinic/models/input_line.py

from netforce.model import Model, fields

class Invoice(Model):
    _name="clinic.invoice"
    _string="Clinic Invoice"

    _fields={
        'je_id': fields.Many2One("clinic.je","Journal Entry"),
        'invoice_id': fields.Many2One("account.invoice","NF Invoice"),
        'amount': fields.Float("Amount"),
    }

Invoice.register()