code: protected function ensureFacadeExists($alias)
      {
          if (file_exists($path = storage_path('cache/facade-'.sha1($alias).'.php'))) {
              return $path;
          }
  
          file_put_contents($path, $this->formatFacadeStub(
              $alias, file_get_contents(__DIR__.'/stubs/facade.stub')
          ));
  
          return $path;
      }
docs: Ensure that the given alias has an existing real-time facade class.
  
  @param  string  $alias
  @return string