Issues with migrations " Cannot declare class ... because the name is already in use "

I have recently started creating my first app for NextCloud, and I have a issue when I am trying to create my first migration.

Inside “nfinkop\lib\Migratio” I only have one single migration file and it’s content looks like this

namespace OCA\NfInkop\Migrations;

use Closure;
use OCP\DB\ISchemaWrapper;
use OCP\Migration\SimpleMigrationStep;
use OCP\Migration\IOutput;

 * This script will create the necessary database tables for nfinkop app
class Version000002Date202401250830 extends SimpleMigrationStep {

 	public function preSchemaChange(IOutput $output, Closure $schemaClosure, array $options) {

	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options) {
		/** @var ISchemaWrapper $schema */
		$schema = $schemaClosure();

		// Supplier
		//if (!$schema->hasTable('nfinkop_supplier')) {
		//	$table = $schema->createTable('nfinkop_supplier');
		//	$table->addColumn('id', 'integer', ['autoincrement' => true,'notnull' => true,]);
		//	$table->addColumn('name', 'string', ['notnull' => true, 'length' => 200]);
		//	$table->addColumn('last_order', 'date');
		//	$table->setPrimaryKey(['id']);
		//	//$table->addIndex(['user_id'], 'nfinkop_user_id_index');
		// Products
		//	$table = $schema->createTable('nfinkop_products');
		//// Orders
		//	$table = $schema->createTable('nfinkop_orders');
		return $schema;

The error message I get (using docker exec -ti master-nextcloud-1 tail -f data/nextcloud.log)

"user":"admin","app":"PHP","method":"POST","url":"/index.php/settings/apps/enable","message":"Cannot declare class OCA\\NfInkop\\Migrations\\Version000001Date202401250830, because the name is already in use at /var/www/html/apps-extra/nfinkop/lib/Migration/Version000001Date202401250830.php#0", ...

Are you using docker or something else that might introduce bind mounts?

You could check with cd /var/www/html && grep Version000001Date202401250830 . -R to see which files have the string in them. There should be exactly one. (Side-note this is only 99% watertight.)