I am having quite a few issues getting the reference API code at https://developers.cloudflare.com/workers-ai/models/llm/ to work?

{'errors': [{'code': 'invalid_union', 'unionErrors': [{'issues': [{'code': 'invalid_type', 'expected': 'object', 'received': 'string', 'path': ['body'], 'message': 'Expected object, received string'}], 'name': 'ZodError'}, {'issues': [{'code': 'invalid_type', 'expected': 'object', 'received': 'string', 'path': ['body'], 'message': 'Expected object, received string'}], 'name': 'ZodError'}], 'path': ['body'], 'message': 'Invalid input'}], 'success': False, 'result': {}}