def enrich_and_concat(files, out_file):
graph = Graph()
for sourcefile in files:
graph.load(sourcefile, format="turtle")
skosify = Skosify()
# Enrichments: broader <-> narrower, related <-> related
logger.debug("Skosify: Enriching relations")
skosify.enrich_relations(graph, False, True, True)
with open(out_file + ".tmp", "w") as handle:
graph.serialize(handle, format="turtle")
os.rename(out_file + ".tmp", out_file)
return len(graph)