无法在石墨烯测试中使用字符串化JSON

我正在尝试编写一个测试,为我的一个字段(questionData)接受字符串化的json值,但失败了:

        query = '''mutation {
            createScorecard(
                name: "Test Scorecard",
                creatorId: 395549257913,
                questionData: "[{\"title\":\"This is a test question\",\"description\":\"Test question description\",\"answers\":[{\"text\":\"Yes\",\"point\":50,\"autofail\":true},{\"text\":\"No\",\"point\":50,\"autofail\":false}]}]"
            ) {
                scorecard {
                    name
                }
                error
            }
        }'''

{'errors':[{'message':'语法错误图形QL(5:40)应为:,找到字符串:“\n\n4:creatorId:395549257913,\n5:questionData:[{“title”:“这是一个测试问题”,“description”:“测试问题描述”,“答案”:[{“text”:“Yes”,“point”:50,“autofail”:true},{“text”:“No”,“point”:50,“autofail”:false}]]]]\n^n6:){\n,“位置”:[{line:5,“column:40}]}