# File lib/sinatra/namespace.rb, line 205
      def set(key, value = self, &block)
        raise ArgumentError, "may not set #{key}" if key != :views
        return key.each { |k,v| set(k, v) } if block.nil? and value == self
        block ||= proc { value }
        singleton_class.send(:define_method, key, &block)
      end