A custom UpdateView to set initial data and save the user profile with a custom group field

views.py

from django.contrib.auth.models import User
from django.views.generic import UpdateView

from .forms import UserProfileForm

class UserProfileUpdateView(UpdateView):
    model = User
    
    def get_initial(self):
        initial = super(UserProfileUpdateView, self).get_initial()
        try:
            current_group = self.object.groups.get()
        except:
            # exception can occur if the edited user has no groups
            # or has more than one group
            pass
        else:
            initial['group'] = current_group.pk
        return initial
    
    def get_form_class(self):
        return UserProfileForm
    
    def form_valid(self, form):
        self.object.groups.clear()
        self.object.groups.add(form.cleaned_data['group'])
        return super(UserProfileUpdateView, self).form_valid(form)