H have a problem in Body (JSON object, use <> for dynamic values) API

there are some wrong in this code:

“model”: “gpt-4-vision-preview”,
“messages”: [
{
“role”: “user”,
“content”: [
{
“type”: “text”,
“text”: “”
},
{
“type”: “image_url”,
“image_url”: {
“url”: “”
}
}
]
}
],
“max_tokens”: 300
}’

and i don’t know what is, please help me