code: def put_annotation(self, key, value):
          
          entity = self.get_trace_entity()
          if entity and entity.sampled:
              entity.put_annotation(key, value)
docs: Annotate current active trace entity with a key-value pair.
          Annotations will be indexed for later search query.
  
          :param str key: annotation key
          :param object value: annotation value. Any type other than
              string/number/bool will be dropped