如何验证嵌套映射中的必需项

def validate_nested_mapping(nested_mapping, required_fields):
    for field in required_fields:
        if field not in nested_mapping:
            raise Exception(f"Missing required field: {field}")
        elif isinstance(nested_mapping[field], dict):
            validate_nested_mapping(nested_mapping[field], required_fields)

# 示例数据
nested_mapping = {
    "name": "John",
    "age": 30,
    "address": {
        "street": "123 Main St",
        "city": "New York",
        "country": "USA"
    }
}

# 必需的字段列表
required_fields = ["name", "address", "street", "city"]

# 验证嵌套映射中的必需项
try:
    validate_nested_mapping(nested_mapping, required_fields)
    print("Validation successful")
except Exception as e:
    print(f"Validation failed: {str(e)}")