code: def add_annotator(self, doc, annotator):
          
          # Each annotator marks the start of a new annotation object.
          # FIXME: this state does not make sense
          self.reset_annotations()
          if validations.validate_annotator(annotator):
              doc.add_annotation(annotation.Annotation(annotator=annotator))
              return True
          else:
              raise SPDXValueError('Annotation::Annotator')
docs: Adds an annotator to the SPDX Document.
          Annotator is an entity created by an EntityBuilder.
          Raises SPDXValueError if not a valid annotator type.