System: Acting as an API optimization expert, examine API documentation and testing history to generate unique parameters. Ensure the parameters are different from all previous attempts. Return only the parameter dictionary.
User: Analyze this API:
Endpoint: https://api.songzixian.com/api/text-to-speech
Method: POST
Required: [{'name': 'text', 'type': 'string', 'description': '要转换的文本内容', 'default': ''}, {'name': 'voice', 'type': 'string', 'description': '选择语音角色，例如：xiaoyun、xiaoming等', 'default': 'xiaoyun'}, {'name': 'speed', 'type': 'int', 'description': '语音播放速度，取值范围1-10，默认为5', 'default': 5}, {'name': 'volume', 'type': 'int', 'description': '语音播放音量，取值范围1-10，默认为5', 'default': 5}, {'name': 'pitch', 'type': 'int', 'description': '语音播放音调，取值范围1-10，默认为5', 'default': 5}, {'name': 'format', 'type': 'string', 'description': '输出文件格式，如mp3、wav等，默认为mp3', 'default': 'mp3'}, {'name': 'appid', 'type': 'string', 'description': '应用ID，用于验证调用者身份', 'default': ''}, {'name': 'sign', 'type': 'string', 'description': '签名，用于验证请求的合法性', 'default': ''}]
Optional: []
Test history: Initial Attempt 1:
Parameters: {'text': 'Hello, how are you?', 'voice': 'xiaoming', 'speed': 7, 'volume': 6, 'pitch': 4, 'format': 'wav', 'appid': 'your_app_id', 'sign': 'your_signature'}
Result: Success
Analysis: Success - parameters worked well

Initial Attempt 2:
Parameters: {'text': 'The quick brown fox jumps over the lazy dog.', 'voice': 'xiaoyun', 'speed': 3, 'volume': 8, 'pitch': 6, 'format': 'mp3', 'appid': 'new_app_id', 'sign': 'new_signature'}
Result: Success
Analysis: Success - parameters worked well

Recent Attempt 3:
Parameters: {'text': 'The future of technology is bright.', 'voice': 'xiaoyun', 'speed': 6, 'volume': 5, 'pitch': 7, 'format': 'mp3', 'appid': 'new_unique_app_id', 'sign': 'new_unique_signature'}
Result: Success
Analysis: Success - parameters worked well

Recent Attempt 4:
Parameters: {'text': 'Exploring the wonders of the universe.', 'voice': 'xiaoming', 'speed': 8, 'volume': 3, 'pitch': 5, 'format': 'mp3', 'appid': 'new_exploration_app_id', 'sign': 'new_exploration_signature'}
Result: Success
Analysis: Success - parameters worked well

Recent Attempt 5:
Parameters: {'text': 'The stars are shining bright tonight.', 'voice': 'xiaoyun', 'speed': 5, 'volume': 5, 'pitch': 5, 'format': 'mp3', 'appid': 'new_app_id_2', 'sign': 'new_signature_2'}
Result: Success
Analysis: Success - parameters worked well

Previously used parameters: - {'appid': 'new_app_id', 'format': 'mp3', 'pitch': '6', 'sign': 'new_signature', 'speed': '3', 'text': 'The quick brown fox jumps over the lazy dog.', 'voice': 'xiaoyun', 'volume': '8'}
- {'appid': 'unique_app_id', 'format': 'wav', 'pitch': '2', 'sign': 'unique_signature', 'speed': '4', 'text': 'The sun is shining brightly today.', 'voice': 'xiaoming', 'volume': '9'}
- {'appid': 'another_app_id', 'format': 'mp3', 'pitch': '8', 'sign': 'another_signature', 'speed': '5', 'text': 'Artificial intelligence is transforming the world.', 'voice': 'xiaoyun', 'volume': '7'}
- {'appid': 'new_unique_app_id', 'format': 'mp3', 'pitch': '7', 'sign': 'new_unique_signature', 'speed': '6', 'text': 'The future of technology is bright.', 'voice': 'xiaoyun', 'volume': '5'}
- {'appid': 'your_app_id', 'format': 'wav', 'pitch': '4', 'sign': 'your_signature', 'speed': '7', 'text': 'Hello, how are you?', 'voice': 'xiaoming', 'volume': '6'}
- {'appid': 'new_exploration_app_id', 'format': 'mp3', 'pitch': '5', 'sign': 'new_exploration_signature', 'speed': '8', 'text': 'Exploring the wonders of the universe.', 'voice': 'xiaoming', 'volume': '3'}
- {'appid': 'new_app_id_2', 'format': 'mp3', 'pitch': '5', 'sign': 'new_signature_2', 'speed': '5', 'text': 'The stars are shining bright tonight.', 'voice': 'xiaoyun', 'volume': '5'}

Based on previous attempts, generate an optimized parameter set that hasn't been used before.
Assistant: