docs: def get_licenses(service_instance, license_manager=None):
      '''
      Returns the licenses on a specific instance.
  
      service_instance
          The Service Instance Object from which to obrain the licenses.
  
      license_manager
          The License Manager object of the service instance. If not provided it
          will be retrieved.
      '''
  
      if not license_manager:
          license_manager = get_license_manager(service_instance)
      log.debug('Retrieving licenses')
      try:
          return license_manager.licenses
      except vim.fault.NoPermission as exc:
          log.exception(exc)
          raise salt.exceptions.VMwareApiError(
              'Not enough permissions. Required privilege: '
              '{0}'.format(exc.privilegeId))
      except vim.fault.VimFault as exc:
          log.exception(exc)
          raise salt.exceptions.VMwareApiError(exc.msg)
      except vmodl.RuntimeFault as exc:
          log.exception(exc)
          raise salt.exceptions.VMwareRuntimeError(exc.msg)