curl --location --request POST 'https://api.baichuan-ai.com/v1/files/' \
--header 'Authorization: Bearer $API_KEY'
{
"id": "file-abc123",
"object": "file",
"bytes": 120000,
"created_at": 1677610602,
"filename": "mydata.pdf",
"purpose": "knowledge-base"
}