How to get all checked items in SelectMultipleField in WTForms + Flask

Question

I have a SelectMultipleField but when I try to access checked items, thought form.fields.data I only get the first of them. More over, by trying to get answers directly from request.form.data through

        for key in request.form.keys():
            print(str(key) + '=' + str(request.form.getlist(key)))

I can see an array of all checked items there.

Where have I made a mistake, so WTForms can't pass all checked items to form.fields.data?

My route:

    form = ListForm()

    if request.method == "GET":
        form.add_items(bank.get_items())
    elif request.method == "POST":
        print(form.fields.data) # and in needed field i only see 'A' even if 'A', 'B' and 'C' checked

form itself:

class Item(FlaskForm):
    pass

class ListForm(FlaskForm):
    fields = FieldList(FormField(Item))
    submit = SubmitField('Submit')

    def add_items(self, items):
        for item in items:
            Item.choices_field = SelectMultipleField(
                choices=item.get_choices()
            ) # lets just assume get_choices() returned ['A', 'B', 'C', 'D'] for an element

            self.fields.append_entry()

and my template for it:

        {{ form.hidden_tag() }}
        <form method="post" novalidate>
                {% for field in form.fields %}
                        <fieldset>
                               {{ field.choices_field }}
                        </fieldset>
                {% endfor %}
                {{ form.submit }}
        </form>

I tried using tuples instead of list of options but had the same issue

Answer 1

So the answer is in getting answers from request.form instead of form.data.