Adjusting for rdflib.Graph.serialize interface change in 6.0
Caused by rdflib/rdflib#1183
@@ -152,7 +152,7 @@ using contexts. The code below shows how to do that::
>>> # Serialize the data in the nquads format so we can see that all of our
>>> # statements are in the proper context
- >>> print(g.serialize(format='nquads').decode('UTF-8'))
+ >>> print(g.serialize(format='nquads', encoding='UTF-8').decode('UTF-8'))
<http://example.org/BDW/entities/Widget#12> <http...> <http://example.org/data/imports/BDW_Widgets_2017-2018> .
<http://example.org/BDW/entities/Widget#12> <...
