Why the name of the form variable is being displayed? django

Question

I have this form

form.py

from django import forms
from .models import User

LETTERS= [
    ('a', 'a)'),
    ('b', 'b)'),
    ('c', 'c)'),
    ('d', 'd)'),
    ('e', 'e)'),

    ]
class CHOICES(forms.Form):
    NUMS = forms.ChoiceField(widget=forms.RadioSelect, choices=LETTERS)

and this view views.py

from django.shortcuts import render
from questoes.models import Questao
from .forms import CHOICES

# Create your views here.
def prova(request):
    questoes = Questao.objects.order_by('?')[:5]
    form = CHOICES
    if request.method=='POST':
        dados = {
            'questoes': questoes, 
            'form':form(request.POST)
        }
        return render(request,'provas/prova.html', dados)
    else:
        dados = {
            'questoes': questoes, 
            'form':form
        }
        return render(request,'provas/prova.html', dados)      

I can't figure out why the name NUMS (the form's variable name) is being rendered in the HTML. :(