Removed unused imports in makemigrations

from django.apps import apps

from django.core.management.base import BaseCommand, CommandError

from django.db import connections, DEFAULT_DB_ALIAS, migrations

from django.db.migrations.migration import Migration

from django.db.migrations import Migration

from django.db.migrations.loader import MigrationLoader

from django.db.migrations.autodetector import MigrationAutodetector

from django.db.migrations.questioner import MigrationQuestioner, InteractiveMigrationQuestioner

                    biggest_number = max([x for x in numbers if x is not None])

                except ValueError:

                    biggest_number = 1

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

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

                    "dependencies": [(app_label, migration.name) for migration in merge_migrations],

                })

                new_migration = subclass("%04i_merge" % (biggest_number + 1), app_label)