THIS CODE RUN

def name_get(self):

            def _name_get(d):

                name = d.get('name', '')

                identity_no = d.get('identity_no', '')

                reg = '%s ( %s )' % (name, identity_no)

                return (d['id'], reg)

            result = list(map(_name_get, self.read(['name', 'identity_no'])))

            return result

BUT I WANT GIVE A CONDITION LIKE THIS

@api.multi

    def name_get(self):

        if self.identity_no != False :

            def _name_get(d):

                name = d.get('name', '')

                identity_no = d.get('identity_no', '')

                reg = '%s ( %s )' % (name, identity_no)

                return (d['id'], reg)

            result = list(map(_name_get, self.read(['name', 'identity_no'])))

        else :

            def _name_get(d):

                name = d.get('name', '')

                return (d['id'], name)

            result = list(map(_name_get, self.read(['name'])))

        return result

File "/home/ubuntu/mycompany/addons/v11_company_custom/base/partner.py", line 44, in name_get
    if self.identity_no != False :
  File "/home/ubuntu/mycompany/gigerhe/fields.py", line 935, in __get__
    record.ensure_one()
  File "/home/ubuntu/mycompany/gigerhe/models.py", line 4365, in ensure_one
    raise ValueError("Expected singleton: %s" % self)
ValueError: Expected singleton: res.partner(857, 825, 77, 83, 69, 42, 840, 806)