cubicweb-dataio #3774877 RDFStore should use sets instead of lists to avoid relations duplication [validation pending]

prioritynormal
typebug
done in0.5.0
load0.100
load left0.000
closed by#fecc8272a613 [dataimport] RDFStore should use sets instead of lists to avoid relations duplication, closes #3774877
patch[dataimport] RDFStore should use sets instead of lists to avoid relations duplication, closes #3774877 [applied]