def graph_to_prov(g):
"""
Convert a `MultiDiGraph
<https://networkx.github.io/documentation/stable/reference/classes/multidigraph.html>`_
that was previously produced by :func:`prov_to_graph` back to a
:class:`~prov.model.ProvDocument`.
:param g: The graph instance to convert.
"""
prov_doc = ProvDocument()
for n in g.nodes():
if isinstance(n, ProvRecord) and n.bundle is not None:
prov_doc.add_record(n)
for _, _, edge_data in g.edges(data=True):
try:
relation = edge_data['relation']
if isinstance(relation, ProvRecord):
prov_doc.add_record(relation)
except KeyError:
pass
return prov_doc
