code: def install_all_labels(stdout=None):
      
  
      if not stdout:
          stdout = sys.stdout
  
      def subsub(kls):  # recursively return all subclasses
          return kls.__subclasses__() + [g for s in kls.__subclasses__() for g in subsub(s)]
  
      stdout.write("Setting up indexes and constraints...\n\n")
  
      i = 0
      for cls in subsub(StructuredNode):
          stdout.write('Found {0}.{1}\n'.format(cls.__module__, cls.__name__))
          install_labels(cls, quiet=False, stdout=stdout)
          i += 1
  
      if i:
          stdout.write('\n')
  
      stdout.write('Finished {0} classes.\n'.format(i))
docs: Discover all subclasses of StructuredNode in your application and execute install_labels on each.
      Note: code most be loaded (imported) in order for a class to be discovered.
  
      :param stdout: output stream
      :return: None