lab.rb

require 'geokit'

module Klasso
  class Client
    attr_reader :api_key
    
    def initialize(api_key)
      @api_key = api_key
    end

    p Geokit::Geocoders::GoogleGeocoder.api_key = api_key
   end
end


#lab.rb:11:in `<class:Client>': undefined local variable or method `api_key' for Klasso::Client:Class (NameError)