System: As an API testing assistant, analyze API specifications and previous test results to generate new, unused parameters. Avoid using any parameters from the previous attempts. Return only the parameter dictionary.
User: API Specification:
URL: https://apis.map.qq.com/ws/distance/v1
Method: GET
Required Parameters: [{'name': 'key', 'type': 'string', 'description': 'api_key', 'default': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI'}, {'name': 'mode', 'type': 'string', 'description': '计算方式：driving（驾车）、walking（步行）。默认：driving', 'default': 'driving'}, {'name': 'from', 'type': 'string', 'description': '起点坐标，格式：lat，lng;lat，lng...（经度与纬度用英文逗号分隔，坐标间用英文分号分隔）', 'default': ''}, {'name': 'to', 'type': 'string', 'description': '终点坐标，格式：lat，lng;lat，lng...（经度与纬度用英文逗号分隔，坐标间用英文分号分隔）', 'default': ''}]
Optional Parameters: [{'name': 'output', 'type': 'string', 'description': '返回格式', 'default': ''}, {'name': 'callback', 'type': 'string', 'description': 'JSONP方式回调函数', 'default': ''}]
Previous attempts: Initial Attempt 1:
Parameters: {'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'from': '39.9042,116.4074', 'to': '34.0522,-118.2437', 'output': 'json', 'callback': 'myCallbackFunction'}
Result: Failed
Analysis: Failed - possible issues: Message from API: 参数错误，坐标错误

Initial Attempt 2:
Parameters: {'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'driving', 'from': '31.2304,121.4737', 'to': '52.5200,13.4050', 'output': 'xml', 'callback': 'newCallbackFunction'}
Result: Failed
Analysis: Failed - possible issues: Message from API: 参数错误，坐标错误

Recent Attempt 3:
Parameters: {'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'from': '40.7128,-74.0060', 'to': '34.0522,-118.2437', 'output': 'json', 'callback': 'anotherCallbackFunction'}
Result: Failed
Analysis: Failed - possible issues: Message from API: 参数错误，坐标错误

Recent Attempt 4:
Parameters: {'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'from': '37.7749,-122.4194', 'to': '34.0522,-118.2437', 'output': 'json', 'callback': 'uniqueCallbackFunction'}
Result: Failed
Analysis: Failed - possible issues: Message from API: 参数错误，坐标错误

Recent Attempt 5:
Parameters: {'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'driving', 'from': '34.0522,-118.2437', 'to': '36.1699,-115.1398', 'output': 'json', 'callback': ''}
Result: Failed
Analysis: Failed - possible issues: Message from API: 参数错误，坐标错误

Already used parameters: - {'callback': '', 'from': '48.8566,2.3522', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'driving', 'output': 'json', 'to': '51.5074,-0.1278'}
- {'callback': 'myCallbackFunction', 'from': '39.9042,116.4074', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'output': 'json', 'to': '34.0522,-118.2437'}
- {'callback': 'newCallbackFunction', 'from': '31.2304,121.4737', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'driving', 'output': 'xml', 'to': '52.5200,13.4050'}
- {'callback': '', 'from': '34.0522,-118.2437', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'driving', 'output': 'json', 'to': '36.1699,-115.1398'}
- {'callback': 'anotherCallbackFunction', 'from': '40.7128,-74.0060', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'output': 'json', 'to': '34.0522,-118.2437'}
- {'callback': 'uniqueCallbackFunction', 'from': '37.7749,-122.4194', 'key': '6LDBZ-BF4HK-G2ZJA-ABCNH-3A44S-7OFZI', 'mode': 'walking', 'output': 'json', 'to': '34.0522,-118.2437'}

Rules:
1. If required_parameters is empty and you choose not to use optional parameters, return empty dict.
2. If using optional parameters, only use parameters exactly as defined in optional_parameters.
3. Do not create new parameters that are not in the specification.

Generate valid parameters:
Assistant: