'If the system is only used by a single Site then this can be defaulted/hidden
- if-appropriate can also use lazy settings to set this from the user.site_id'

def get_org_default_site(self):

    default_site = self.org.get('default_site', None)
    if default_site:
        if (not isinstance(default_site, (int, long))):
            default_site_id = current.session.s3.default_site_id
            if default_site_id:
                default_site = default_site_id
            else:
                table = current.s3db.org_site
                site = current.db((table.name == default_site)).select(table.site_id, limitby=(0, 1)).first()
                try:
                    default_site = site.site_id
                    current.session.s3.default_site_id = default_site
                except:
                    current.log.error(('Default    Site    not    found:    %s' % default_site))
                    default_site = None
    return default_site
