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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 _to_bel_lines_body(graph) -> Iterable[str]: """Iterate the lines of a BEL graph's corresponding BEL script's body. :param pybel.BELGraph graph: A BEL graph """

    qualified_edges = sort_qualified_edges(graph)

    for citation, citation_edges in group_citation_edges(qualified_edges):
        yield 'SET Citation = {{{}}}\n'.format(citation)

        for evidence, evidence_edges in group_evidence_edges(citation_edges):
            yield 'SET SupportingText = "{}"'.format(evidence)

            for u, v, _, data in evidence_edges:
                annotations_data = data.get(ANNOTATIONS)

                keys = sorted(annotations_data) if annotations_data is not None else tuple()
                for key in keys:
                    yield _set_annotation_to_str(annotations_data, key)

                yield graph.edge_to_bel(u, v, data)

                if keys:
                    yield _unset_annotation_to_str(keys)

            yield 'UNSET SupportingText'
        yield 'UNSET Citation\n'
        yield '#' * 80