<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def form_out(self, _form=None):
 """ Renders form. Applies form modifiers, then writes result to response payload. If supplied, given form object instance will be used instead of view's default ObjectForm. Args: _form (:py:attr:`~zengine.forms.json_form.JsonForm`):
 Form object to override `self.object_form` """

        _form = _form or self.object_form
        self.output['forms'] = _form.serialize()
        self._add_meta_props(_form)
        self.output['forms']['grouping'] = _form.Meta.grouping
        self.output['forms']['constraints'] = _form.Meta.constraints
        self._patch_form(self.output['forms'])
        self.set_client_cmd('form')