Openapi multiple content-types responses

Multi_content-type.json

{
    "openapi":"3.0.2",
    "info": {
      "title":"Multi content-type generator spec",
      "version":"1.0"
    },
    "servers": [
      {"url":"https://api.server.test/v1"}
    ],
    "paths": {
        "/pdf-or-json": {
            "get": {
                "summary": "Return a .pdf, or a json error",
                "operationId": "getPdfOrJson",
                "parameters": [],
                "responses": {
                    "200": {
                        "description": "OK",
                        "content": {
                            "application/pdf": {
                                "schema": {
                                    "type": "string",
                                    "format": "binary"
                                }
                            }
                        },
                        "headers": {}
                    },
                    "404": {
                        "description": "Not found",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object",
                                    "properties": {
                                        "error-message": {
                                            "type": "string"
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        },
    }
  }