You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: chainable.rb
    path of file: ./repos/openproject/modules/reporting/lib/report
    
    the code of the file until where you have to start completion: #-- copyright
# OpenProject is an open source project management softwa
    
    def initialize(child = nil, options = {})
      @options = options
      options.each do |key, value|
        unless self.class.extra_options.include? key
          raise ArgumentError, "may not set #{key}" unless engine.accepted_properties.include? key.to_s

          send :"#{key}=", value
        end
      end