HTTP 400 Bad Request
Allow: POST, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "key": [
        "Please enter a valid key." 
    ],
    "user": [
        "Please enter a valid user." 
    ],
    "dict": [
        "Please enter a valid dict." 
    ],
    "model": [
        "Please enter a valid model." 
    ]
}