Hello, i need to make property that is of type List of Lists of String (see "body_text" in JSON)

How can i make it?

Thanks

{
  "type": "BODY",
  "text": "<TEXT>",
  
  # Required if <TEXT> string contains variables
  "example": {
    "body_text": [
      [
        <BODY_TEXT>
      ]
    ]
  }
}