flask - Rendering a WTForms CheckboxInput in Jinja Template -

i can't seem figure out how render wtforms checkboxinput in template. when try render field using flask in jinja template error:

typeerror: call() takes 2 arguments (1 given)

the error has how {{ form.prefs(value='n') }} used in template. wtforms documentation checkboxinput says "the value= html attribute default ‘y’ unless otherwise specified value= @ rendering." error whether specify value or not.

i can't seem find example of how render simple checkboxinput. appreciated.

here's form:

class preferencesform(form):     prefs = widgets.checkboxinput() 

here's template:

{% extends "base.html" %}  {% block content %}  <form method="post" action="/user/prefs/">     <div>{{ form.prefs(value='n') }}</div>     <button type="submit" class="btn">submit</button>     </form>  {% endblock %} 

you supposed use booleanfield instead of directly using widget:

class preferencesform(form):     prefs = booleanfield() 

and in template:

{{ form.prefs(value='n') }} 

---

the general idea use 1 of fields in form class, automatically assign proper widget display. , widgets are:

... classes purpose render field usable representation, xhtml. when field called, default behaviour delegate rendering widget. abstraction provided widgets can created customize rendering of existing fields.

^{emphasis mine}

further, widget needs field instance render itself:

def __call__(self, field, **kwargs):     if getattr(field, 'checked', field.data):         kwargs['checked'] = true     return super(checkboxinput, self).__call__(field, **kwargs)