Django GroupRequiredMixin to check if user is in one or more groups

group_required_mixins.py

class GroupRequiredMixin(AccessMixin):
    group_required = None

    def get_group_required(self):
        """Get which group's membership is required"""
        if any([
            self.group_required is None,
            not isinstance(self.group_required, (list, tuple, str))
        ]):
            raise ImproperlyConfigured(
                f'{self.__class__.__name__} requires the `group_required` attribute '
                "to be set and be a string, list, or tuple."
            )
        if not isinstance(self.group_required, (list, tuple)):
            self.group_required = (self.group_required,)
        return self.group_required

    def check_membership(self, request, groups):
        """Check for user's membership in required groups. Superusers are
        automatically members"""
        if self.request.user.is_superuser:
            return True

        user_groups = self.request.user.groups.values_list("name", flat=True)
        return set(groups).intersection(set(user_groups))

    def dispatch(self, request, *args, **kwargs):
        """Call the appropriate handler if the user is a group member"""
        in_group = False
        if request.user.is_authenticated:
            in_group = self.check_membership(request. self.get_group_required())

        if not in_group:
            return self.handle_no_permission()

        return super().dispatch(request, *args, **kwargs)