def get_filter_arg(self, index, flt):
        if self.named_filter_urls:
            name = ('%s %s' % (flt.name, as_unicode(flt.operation()))).lower()
            name = filter_char_re.sub('', name)
            name = filter_compact_re.sub('_', name)
            return name
        else:
            return str(index)
Given a filter `flt`, return a unique name for that filter in
dataset/ETHPy150Open flask-admin/flask-admin/flask_admin/model/base.py/BaseModelView.get_filter_arg