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://gaialens-historical-esg-scores.p.rapidapi.com/scores/historical/{year}
Method: GET
Required: [{'name': 'year', 'type': 'string', 'description': 'The year for which historical scores are requested. Must be less than or equal to 2020.', 'default': '2020'}]
Optional: [{'name': 'Content-Type', 'type': 'string', 'description': 'Specifies the media type of the resource.', 'default': ''}, {'name': 'sedol', 'type': 'string', 'description': 'The SEDOL code for the company.', 'default': ''}, {'name': 'isin', 'type': 'string', 'description': 'The ISIN code for the company.', 'default': ''}, {'name': 'companyname', 'type': 'string', 'description': 'The name of the company for which scores are requested.', 'default': 'Apple Inc.'}]
Test history: Initial Attempt 1:
Parameters: {'year': '2019', 'Content-Type': 'application/json', 'sedol': 'B1Y8QZ3', 'isin': 'US0378331005', 'companyname': 'Microsoft Corp'}
Result: Failed
Analysis: Failed - possible issues: Message from API: Bad request syntax or unsupported method - invalid request parameter(s)

Initial Attempt 2:
Parameters: {'year': '2020', 'Content-Type': 'application/json', 'sedol': 'B1Y8QZ4', 'isin': 'US02079K3059', 'companyname': 'Tesla Inc.'}
Result: Failed
Analysis: Failed - possible issues: Message from API: Bad request syntax or unsupported method - invalid request parameter(s)

Recent Attempt 3:
Parameters: {'year': '2018', 'Content-Type': 'application/vnd.api+json', 'sedol': 'B1Y8QZ7', 'isin': 'US0378331007', 'companyname': 'Netflix Inc.'}
Result: Failed
Analysis: Failed - possible issues: Message from API: Bad request syntax or unsupported method - invalid request parameter(s)

Recent Attempt 4:
Parameters: {'year': '2020', 'Content-Type': 'application/json', 'sedol': 'B1Y8QZ8', 'isin': 'US02079K3075', 'companyname': 'Facebook Inc.'}
Result: Failed
Analysis: Failed - possible issues: Message from API: Bad request syntax or unsupported method - invalid request parameter(s)

Recent Attempt 5:
Parameters: {'year': '2020', 'Content-Type': 'application/xml', 'sedol': 'B1Y8QZ9', 'isin': 'US02079K3083', 'companyname': 'Oracle Corporation'}
Result: Failed
Analysis: Failed - possible issues: Message from API: Bad request syntax or unsupported method - invalid request parameter(s)

Previously used parameters: - {'Content-Type': 'application/json', 'companyname': 'Microsoft Corp', 'isin': 'US0378331005', 'sedol': 'B1Y8QZ3', 'year': '2019'}
- {'Content-Type': 'application/xml', 'companyname': 'Google LLC', 'isin': 'US0378331006', 'sedol': 'B1Y8QZ5', 'year': '2020'}
- {'Content-Type': 'application/json', 'companyname': 'Facebook Inc.', 'isin': 'US02079K3075', 'sedol': 'B1Y8QZ8', 'year': '2020'}
- {'Content-Type': 'application/xml', 'companyname': 'Oracle Corporation', 'isin': 'US02079K3083', 'sedol': 'B1Y8QZ9', 'year': '2020'}
- {'Content-Type': 'text/plain', 'companyname': 'Amazon.com Inc.', 'isin': 'US02079K3067', 'sedol': 'B1Y8QZ6', 'year': '2020'}
- {'Content-Type': 'application/vnd.api+json', 'companyname': 'Netflix Inc.', 'isin': 'US0378331007', 'sedol': 'B1Y8QZ7', 'year': '2018'}
- {'Content-Type': 'application/json', 'companyname': 'Tesla Inc.', 'isin': 'US02079K3059', 'sedol': 'B1Y8QZ4', 'year': '2020'}

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