Which Harper Lee book was not published in the 20th Century?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q639669', 'id': 0, 'label': 'musician'}, {'type': 'INTERNAL', 'name_': 'Q272719', 'id': 1, 'label': 'Alice Ghostley'}, {'type': 'INTERNAL', 'name_': 'Q177922', 'id': 2, 'label': 'To Kill a Mockingbird'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q182658', 'id': 3, 'label': 'Harper Lee'}], 'links': [{'name_': 'P106', 'source': 1, 'target': 0, 'label': 'occupation'}, {'name_': 'P161', 'source': 2, 'target': 1, 'label': 'cast member'}, {'name_': 'P58', 'source': 2, 'target': 3, 'label': 'screenwriter'}]}