How many main Witcher games are there?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q1860', 'id': 0, 'label': 'English'}, {'type': 'INTERNAL', 'name_': 'Q14915517', 'id': 1, 'label': 'PEGI 18'}, {'type': 'INTERNAL', 'name_': 'Q38712', 'id': 2, 'label': '18'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q201', 'id': 3, 'label': '3'}, {'type': 'INTERNAL', 'name_': 'Q24591290', 'id': 4, 'label': 'Gwent: The Witcher Card Game'}, {'type': 'INTERNAL', 'name_': 'Q917272', 'id': 5, 'label': 'The Witcher 2: Assassins of Kings'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q18935909', 'id': 6, 'label': 'The Witcher'}, {'type': 'INTERNAL', 'name_': 'Q115647497', 'id': 7, 'label': 'Destiny Amaka'}], 'links': [{'name_': 'P180', 'source': 1, 'target': 2, 'label': 'depicts'}, {'name_': 'P5236', 'source': 2, 'target': 3, 'label': 'prime factor'}, {'name_': 'P407', 'source': 4, 'target': 0, 'label': 'language of work or name'}, {'name_': 'P179', 'source': 4, 'target': 6, 'label': 'part of the series'}, {'name_': 'P908', 'source': 5, 'target': 1, 'label': 'PEGI rating'}, {'name_': 'P179', 'source': 5, 'target': 6, 'label': 'part of the series'}, {'name_': 'P527', 'source': 6, 'target': 5, 'label': 'has part(s)'}, {'name_': 'P1412', 'source': 7, 'target': 0, 'label': 'languages spoken, written or signed'}, {'name_': 'P3373', 'source': 7, 'target': 3, 'label': 'sibling'}]}