# File test/unit/util/observable.rb, line 51

                                def remove_listener(channel_name, listener_key)

                                        channel = channels[channel_name]

                                        unless (channel.nil?)

                                                key = listener_key

                                                if (listener_key.instance_of?(Proc))

                                                        key = ProcWrapper.new(listener_key)

                                                end

                                                if (channel.has_key?(key))

                                                        return channel.delete(key)

                                                end

                                        end

                                        return nil

                                end