How to use form_overrides on ListField(StringField)?

[laiyonghao]

I have a WebPage class to store pages scraped from web.

class WebPage(Document):
    html = fields.StringField()
    top_image = fields.StringField()
    images = fields.ListField(fields.StringField())
    ... other fields.

I Defined a MyImageField to display image fields.

from wtforms import StringField
from wtforms.widgets import Input
from flask import render_template

class MyImageInputWidget(Input):
    def __call__(self, field, **kwargs):
        return render_template(
                "my_image_widget.html",
                field=field,
            )

class MyImageField(StringField):
    widget = MyImageInputWidget()

It is very easy to use with top_image field:

class WebPageModelView(ModelView):
    form_overrides = {
        'top_image': MyImageField,
    }

It looks like

But how to use form_overrides on images field ?