i have created a wizard which is transient model and i have written a function for searching records as:

def key(self, priority):
    priority_dict = {
        1: 'name',
        2: 'membership_id',
        3: 'tracking_id',
    }
    return priority_dict[priority]

def value(self, priority):
    priority_dict = {
        1: self.file_id.name,
        2: self.membership_id.ref,
        3: self.tracking_id,
    }
    return priority_dict[priority].strip()


def search_related_file(self):
    self.return_line.unlink()

    priority_list = [self.file_id, self.membership_id, self.tracking_id, self.member_id]
    priority = 0
    record = []

    if not any(priority_list):
        raise ValidationError(_('Must populate one of the above field for search.'))

    for rec in priority_list:
        if not rec:
            priority = priority + 1
        elif rec:
            priority = priority + 1
            break

    if priority == 4:
        member_id = self.env['res.partner'].search([('cnic', '=', self.member_id)])
        if member_id:
            record = self.env['file'].search([('membership_id', '=', member_id.id)])
    else:
        record = self.env['file'].search([(self.key(priority), '=', self.value(priority))])
        # record = self.env['file'].search([('membership_id','=',self.membership_id.ref)])

    if record:
        for rec in record:
            self.return_line.create({
                'file_id': rec.id,
                'return_id': self.id
            })

    return {
        'type': 'ir.actions.do_nothing'
    }

it is giving me the result of previous search. For example if i search from a file_id field and select 1st file it doesn't return anything but then if i search again with 2nd file option from list then it gives the result of 1st file in one2many field i tried to debug the code it gives the correct records but doesn't return correct records in the wizard. I couldn't understand this behavior because the exact same function is working correctly in version 11. any idea???