code: public function install(InstalledRepositoryInterface $repo, PackageInterface $package)
      {
          $installPath = $this->installPath;
          if (file_exists($installPath) && !$this->filesystem->isDirEmpty($installPath)) {
              throw new \InvalidArgumentException("Project directory $installPath is not empty.");
          }
          if (!is_dir($installPath)) {
              mkdir($installPath, 0777, true);
          }
          $this->downloadManager->download($package, $installPath);
      }
docs: {@inheritDoc}