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: callbacks.rb
    path of file: ./repos/stackneveroverflow/vendor/bundle/ruby/2.3.0/gems/sass-3.4.24/lib/sass
    
    the code of the file until where you have to start completion: module Sass
  # A lightweight infrastructure for defining and running callback
    
    def define_callback(name)
      class_eval <<RUBY, __FILE__, __LINE__ + 1
def on_#{name}(&block)
  @_sass_callbacks = {} unless defined? @_sass_callbacks
  (@_sass_callbacks[#{name.inspect}] ||= []) << block
end

def run_#{name}(*args)
  return unless defined? @_sass_callbacks
  return unless @_sass_callbacks[#{name.inspect}]
  @_sass_callbacks[#{name.inspect}].each {|c| c[*args]}
end
private :run_#{name}
RUBY
    end