hi i change the create method of account method to have a sequence number like sale module and it 's work in draft status , know i want to in posted status to have the same sequence like draft i inherit the next_by_id and _next from ir.sequence but it doesn't work 

this is what i do 

name_seq = fields.Char(string='Order Reference', required=True, copy=False, readonly=True, index=True, default=lambda self: _('New'))


@api.model
def create(self, vals):
    if vals.get('name_seq', _('New')) == _('New'):
            vals['name_seq'] = self.env['ir.sequence'].next_by_code('sequence.piece') or _('New')
    result = super(AccountMove, self).create(vals)
    return result

in the post methode in next_by_id i want to call my name_seq

new_name = sequence.with_context(ir_sequence_date=move.date).next_by_id()

class  IrSequence(models.Model):
    _inherit = "ir.sequence"
    name_seq = fields.Char(string='Order Reference', required=True, copy=False, readonly=True, index=True,
                           default=lambda self: _('New'))

    def _next(self):
        """ Returns the next number in the preferred sequence in all the ones given in self."""

        dt = fields.Date.today()

        seq_date = self.env['account.move'].browse(('id', '=', self.name_seq))

        return seq_date
    @api.multi
    def next_by_id(self):
        """ Draw an interpolated string using the specified sequence."""
        self.check_access_rights('read')
        return self._next()

don't work any help please