def evalCopy(ctx, u):

    src, dst = u.graph

    srcg = _graphOrDefault(ctx, src)
    dstg = _graphOrDefault(ctx, dst)

    if srcg.identifier == dstg.identifier:
        return

    dstg.remove((None, None, None))

    dstg += srcg
Save journal to disk, returns Deferred of finish status.
dataset/ETHPy150Open RDFLib/rdflib/rdflib/plugins/sparql/update.py/evalCopy--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/persisted/journal/base.py/Journal.sync