Flask MultiCheckboxField

MultiCheckboxField.py

from flask import Flask, render_template, request
from flask_wtf import FlaskForm
from wtforms import (SubmitField, SelectMultipleField, widgets)

class MultiCheckboxField(SelectMultipleField):
    widget = widgets.ListWidget(prefix_label=False)
    option_widget = widgets.CheckboxInput()
    
class ExampleForm(FlaskForm):
    nums = MultiCheckboxField('label'
                               coerce=int,
                               choices=[(1, 'one'), (2, 'two'), (3, 'three')],
                               validators=[])
    submit = SubmitField('submit')
   
@app.route('/', methods=['GET', 'POST'])
def index():
    form = ExampleForm()
    if request.method == 'POST':
        # do something
    return render_template('index.html', form=form)