forms.py

from django import forms
from django.core.exceptions import ObjectDoesNotExist
from django.forms.models import modelformset_factory

from .models import Invitee, Extra


class RSVPForm(forms.Form):
    code = forms.CharField(max_length=56)

    def clean(self):
        cleaned_data = super().clean()
        code = cleaned_data.get('code')

        try:
            person = Invitee.objects.get(code=code)
        except ObjectDoesNotExist:
            raise forms.ValidationError(
                    "Your code didn't match any records. Please "
                    "make sure you've typed it correctly, or "
                    "contact us if you feel there's an error."
                    )
        return cleaned_data

class ExtraForm(forms.ModelForm):
    class Meta:
        model = Extra
        fields = ('name',)