vertical-cooperative/easy_my_coop_ch/models/coop.py

from odoo import fields, models


class SubscriptionRequest(models.Model):
    _inherit = 'subscription.request'

    company_type = fields.Selection(selection_add=[
                                    ('ei', 'Individual company'),
                                    ('snc', 'Partnership'),
                                    ('sa', 'Limited company (SA)'),
                                    ('sarl', 'Limited liability company (Ltd)'), #noqa
                                    ('sc', 'Cooperative'),
                                    ('asso', 'Association'),
                                    ('fond', 'Foundation'),
                                    ('edp', 'Company under public law')])

    def get_required_field(self):
        req_fields = super(SubscriptionRequest, self).get_required_field()
        if 'iban' in req_fields:
            req_fields.remove('iban')

        return req_fields

    def check_iban(self, iban):
        if iban:
            return super(SubscriptionRequest, self).check_iban(iban)
        return True