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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _handle_relation(self, tokens: ParseResults) -> str: """Handle a relation."""

        subject_node_dsl = self.ensure_node(tokens[SUBJECT])
        object_node_dsl = self.ensure_node(tokens[OBJECT])

        subject_modifier = modifier_po_to_dict(tokens[SUBJECT])
        object_modifier = modifier_po_to_dict(tokens[OBJECT])

        annotations = {
            annotation_name: (
                {
                    ae: True
                    for ae in annotation_entry
                }
                if isinstance(annotation_entry, set) else
                {
                    annotation_entry: True
                }
            )
            for annotation_name, annotation_entry in self.control_parser.annotations.items()
        }

        return self._add_qualified_edge(
            subject_node_dsl,
            object_node_dsl,
            relation=tokens[RELATION],
            annotations=annotations,
            subject_modifier=subject_modifier,
            object_modifier=object_modifier,
        )