json_schema: {
    "properties": {
      "grade_scale": {
        "properties": {
          "A": {
            "description": "The minimum score for grade A",
            "type": "number"
          },
          "B": {
            "description": "The minimum score for grade B",
            "type": "number"
          },
          "C": {
            "description": "The minimum score for grade C",
            "type": "number"
          },
          "D": {
            "description": "The minimum score for grade D",
            "type": "number"
          }
        },
        "type": "object"
      },
      "score": {
        "description": "The score to calculate the grade for",
        "type": "number"
      }
    },
    "required": [
      "score",
      "grade_scale"
    ],
    "type": "object"
  }