RDFlib serialization of Brick.ttl fails

[bbalaji-ucsd]

BugReport: @joshuagluck found that if you import Brick.ttl in rdflib and serialize it, Protege won’t accept the output.

g = rdflib.Graph()
g.parse('../BuildingSchema/Brick.ttl', format='turtle')
g.serialize(destination='GHCYuvraj_brick.ttl', format='turtle')