How many countries span the Sahara desert?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q1028', 'id': 0, 'label': 'Morocco'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q6583', 'id': 1, 'label': 'Sahara'}, {'type': 'INTERNAL', 'name_': 'Q20155858', 'id': 2, 'label': None}], 'links': [{'name_': 'P17', 'source': 2, 'target': 0, 'label': 'country'}, {'name_': 'P706', 'source': 2, 'target': 1, 'label': 'located in/on physical feature'}]}