code: public function getMigrationClassName()
      {
          $postfix = '_initial_' . $this->tableName;
          if (is_dir($this->migrationDirectory)) {
              $searchExisting = FileHelper::findFiles($this->migrationDirectory, ['only' => [$postfix . '.php']]);
              if (!empty($searchExisting)) {
                  return strstr(basename($searchExisting[0]), '.php', true);
              }
          }
  
          return  'm' . gmdate('ymd_His', $this->migrationTimestamp) . $postfix;
      }
docs: Get migration class name.
  
  @return string the model namespace of the module.