sparql_interface.subgraph.create and sparql_subgraph_interface.subgraph.update behave in opposite way. #39
Description
At the moment, sparql_interface.subgraph.create updates an existing subgraph by adding new triples on top of the existing subgraph in the triplestore and sparql_subgraph_interface.subgraph.update erases the existing subgraph and replaces it with the existing ones.
This should actually behave the other way around.