Your actual response headers will change based on the input request and what you want to allow it to do.
The basic structure should be something like this:
from javax.servlet.http import HttpServletResponse
servletResponse = request["servletResponse"]
servletResponse.addHeader(someCorsHeaders, someCorsValue)
# other headers based on incoming request
servletResponse.setStatus(HttpServletResponse.SC_NO_CONTENT)
See Cross-Origin Resource Sharing (CORS) - HTTP | MDN for reference on what to send in the response.