Mvt:Call headers section

[RayYates]

I'm making a page template mvt:call to the UPS api.
Given the code below. What goes in headers="???????"

The API specs say
Use HTTP/s POST.
The JSON API expects the following HTTP headers:
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Allow-Methods: POST
Access-Control-Allow-Origin: *
Content-Type: application/json

<mvt:call action = "g.url"
        method = "POST"
        content-type = "'application/json'"
        headers = "??????">
    <mvt:assign name="g.return" value="g.return $  s.callvalue" />
</mvt:call>

[wmgilligan]

I would say:

<MvAssign name="l.crlf" value="{  asciichar(13) $ asciichar(10) }">

(

HEADERS="{ 'Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept' $ l.crlf $ 'Access-Control-Allow-Methods: POST' $ l.crlf $ 'Access-Control-Allow-Origin: *' $ l.crlf }" CONTENT-TYPE="application/json"

[RayYates]

Thank you sir!