Use key_name instead of link_id
Some entities do not have a link_id, but all entities are guaranteed
to have a key_name (or an id).
from django.core.management.base import AppCommand, CommandError
class Command(AppCommand):
help = "RENAMED: see 'sqlcustom'"
def handle(self, *apps, **options):
raise CommandError("This command has been renamed. Use the 'sqlcustom' command instead.")