Can we save the graph without conflict?

Property definitions

neo4j $ GraphStore :: isolated_save
	# Can we save the graph without conflict?
	fun isolated_save: Bool is abstract
lib/neo4j/graph/graph.nit:164,2--165,36

neo4j $ Neo4jGraphStore :: isolated_save
	redef fun isolated_save do return not has_node_label(node_label)
lib/neo4j/graph/graph.nit:213,2--65

neo4j $ JsonGraphStore :: isolated_save
	redef fun isolated_save do return true
lib/neo4j/graph/json_graph_store.nit:94,2--39