AppDaemon : how to pass parameters from HA

Third party integrations AppDaemon
1

I’m stucked with the invocation of an app running in AppDaemon from a HA automation. This app makes use of libraries that I can’t afford to have running in the HA docker.
The invocation from HA is based on a rest_command.
The problem comes with parameters :

action: rest_command.get_screenshot
data:
  filename: first_test.pdf
  items: blabla

Here is the definition of the app (apps.yaml) :

screenshot_api:
  module: screenshot_api
  class: ScreenshotAPI
  param1: filename
  param2: items

Is this the correct approach for the HA side ?
If so, how can I get these params available in my app on AppDaemon side ?

class ScreenshotAPI(hass.Hass):
    def initialize(self):
        self.register_endpoint(self.take_screenshots, "screenshot")
        self.log("API 'screenshot' enregistrée. Prête à recevoir des requêtes.")

    def take_screenshots(self, request):
### ? from here how to get my input params ?

Thanks for your help !