Allow squashing of squashed migrations

        try:

            migration = executor.loader.get_migration_by_prefix(app_label, migration_name)

        except AmbiguityError:

            raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (app_label, migration_name))

            raise CommandError("More than one migration matches '%s' in app '%s'. Please be more specific." % (migration_name, app_label))

        except KeyError:

            raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (app_label, migration_name))

            raise CommandError("Cannot find a migration matching '%s' from app '%s'." % (migration_name, app_label))

        # Work out the list of predecessor migrations

        migrations_to_squash = [

            else:

                self.stdout.write("  Optimized from %s operations to %s operations." % (len(operations), len(new_operations)))

        # Work out the value of replaces (any squashed ones we're re-squashing)

        # need to feed their replaces into ours

        replaces = []

        for migration in migrations_to_squash:

            if migration.replaces:

                replaces.extend(migration.replaces)

            else:

                replaces.append((migration.app_label, migration.name))

        # Make a new migration with those operations

        subclass = type("Migration", (migrations.Migration, ), {

            "dependencies": [],

            "operations": new_operations,

            "replaces": [(m.app_label, m.name) for m in migrations_to_squash],

            "replaces": replaces,

        })

        new_migration = subclass("0001_squashed_%s" % migration.name, app_label)