Bug in RDFLib JSON-LD code that drops embedded blank nodes

rdflib-jsonld-bug.py

#!/usr/bin/env python3

from rdflib.serializer import Serializer
from rdflib import Graph, URIRef, BNode, Literal
from rdflib.namespace import FOAF, DCTERMS

g = Graph()
spatial = BNode()
g.add((URIRef('http://example.org/thing'), DCTERMS.spatial, spatial))
g.add((spatial, FOAF.name, Literal('California')))

context = {
	'foaf': 'http://xmlns.com/foaf/0.1/',
	'dcterms': 'http://purl.org/dc/terms/',
}

### Making this True will omit the `foaf:name "California"` data
SHOW_SERIALIZATION_BUG = False

if SHOW_SERIALIZATION_BUG:
	context['dcterms:spatial'] = {'@type': '@id'}

b = g.serialize(format='json-ld', context=context, indent=4)
print(b.decode("utf-8") )