I want to post message on chatter whenever I change the unit price in sale order line, in already created quotation.

this is my py file.

class inheritchat(models.Model):
_inherit = 'sale.order.line'
_inherit = ['mail.thread', 'mail.activity.mixin']

price_unit = fields.Float('Ashu', required=True, digits='Product Price', default=0.0, tracking=True, track_visibility='always')


@api.model
def write(self, vals):
if vals.get('price_unit'):
self.message_post(body=_('updated: %s') % vals.get('price_unit'))
super(inheritchat, self).write(vals)