Unable to pass params to a model method from rabl view

[yo-gen]

Hi.

I have the following rabl file

object false
child @categories => :categories do
  attributes :id,:name
  child :active_channel => :spree_channels do |channel|
    extends("spree/api/yt_categories/channel_show")`
  end
end

I want to know how to pass a parameter from this rabl view to the :active_channel method which is defined in the model.
Passing it like this
:active_model(@current_api_user.id)
doesn't work