code: function(callback) {
          var step = 0
  
          async.whilst(
            function() {
              return ++step <= pp.options.extra
            },
            function(callback) {
              pp.tryPorts = []
              var c = grunt.config.get('port-pick-' + step)
  
              // With multiple tasks, do not find a port that we've already found
              // in a previous task
              if(c) {
                callback()
                return
              }
  
              async.waterfall([
                pp.findPort,
  
                function(selectedPort, callback) {
                  if(selectedPort === false)
                    grunt.fatal('No available port was found')
  
                  grunt.config.set('port-pick-' + this.step, selectedPort)
                  grunt.log.writeln( '>> '.green + 'port-pick-' + this.step + '=' +
                    selectedPort)
  
                  callback()
                }.bind({step: step})
              ],
              function(err) {
                callback()
              })
            },
            function(err) {
              done()
            }
          )
        }
docs: Set some configurations for extra ports template interpolation