Filter for namespaced controllers

I have a set of controllers in the folder /controllers/admin that all look like this and having the same filter:

module Admin
  class UsersController < ApplicationController
    before_action :some_method

    #actions
  end
end

How could each namespaced controller inherit the before_action :some_method from a central place?

It seems you need an individual Base controller within Admin module namespace:

class Admin::BaseController < ApplicationController
  before_action :some_method

  #actions
end

class Admin::UsersController < Admin::BaseController
  #some_method filter is invoked here
end

class Admin::PostsController < Admin::BaseController
  #some_method filter is invoke here
end