def monkeypatched_call(self, field, **kwargs):
    kwargs.setdefault('id', field.id)
if self.multiple:
    kwargs['multiple'] = True
html = ['<select %s>' % html_params(name=field.name, **kwargs)]
for (val, label, selected), (_, methodarg) in zip(field.iter_choices(),
    field._get_object_list()):
    html.append(self.render_option(val, label, selected, **{'data-mid':
        methodarg.mid}))
html.append('</select>')
return HTMLString(''.join(html))
Select.__call__ = monkeypatched_call
flask-admin form: Constrain Value of Field 2 depending on Value of Field 1