How to pass error message for custom permission in Django Rest Framework?

Question

I have a custom permission and it called IsVendor. Now I have two built in permission class and they are IsAdminUser, IsAuthenticated and when I try to hit those url without credentials or login information it shows me an error message like this one 'details':'Authentication Credentials are not provided' and I want the same for my custom permission error message. But it is showing Anonymoususer has no object vendor.

class IsVendor(BasePermission):
    def has_permission(self, request, view):
        if request.user.vendor:
            return True
        else:
            return False

this is my custom permission class. I want to pass error message like 'Authentication Credentials not provided'

Answer 1

Add message Field

class IsVendor(BasePermission):
    message = 'Your Message'
    def has_permission(self, request, view):
        if request.user.vendor:
            return True
        else:
            return False