code: def list_processors(self, instance=None):
          
          # Server does not do pagination on listings of this resource.
          # Return an iterator anyway for similarity with other API methods
          url = '/processors'
          if instance:
              url += '/' + instance
          response = self.get_proto(path=url)
          message = rest_pb2.ListProcessorsResponse()
          message.ParseFromString(response.content)
          processors = getattr(message, 'processor')
          return iter([Processor(processor) for processor in processors])
docs: Lists the processors.
  
          Processors are returned in lexicographical order.
  
          :param Optional[str] instance: A Yamcs instance name.
          :rtype: ~collections.Iterable[.Processor]