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: scheduler_fetch.go
    path of file: ./repos/gleam/distributed/driver/scheduler
    
    the code of the file until where you have to start completion: package scheduler

import (
	"log"
	"math/rand"
	"time"

	"github.com/chrislusf/gleam/distributed/driver/scheduler/market"
	"github.com/chrislusf/gleam/distributed/plan"
	"github.com/chrislusf/gleam/pb"
)

// Requirement is TaskGroup
// Object is Agent's Location
func (s *Scheduler) Fetch(demands []market.Demand) {
	var request pb.ComputeRequest
	request.Username = s.Option.Username
	request.Hostname = s.Option.Hostname
	request.FlowHashCode = s.Option.FlowHashcode
	request.DataCenter = s.Option.DataCenter
	for _, d := r
    
func (s *Scheduler) Fetch(demands []market.Demand) {
	var request pb.ComputeRequest
	request.Username = s.Option.Username
	request.Hostname = s.Option.Hostname
	request.FlowHashCode = s.Option.FlowHashcode
	request.DataCenter = s.Option.DataCenter
	for _, d := range demands {
		taskGroup := d.Requirement.(*plan.TaskGroup)
		requiredResource := taskGroup.RequiredResources()
		request.ComputeResources = append(request.ComputeResources, requiredResource)
	}

	result, err := getResources(s.Master, &request)
	if err != nil {
		log.Printf("%s Failed to allocate: %v", s.Master, err)
		time.Sleep(time.Millisecond * time.Duration(15000+rand.Int63n(5000)))
	} else {
		if len(result.Allocations) == 0 {
			// log.Printf("%s No more new executors.", s.Master)
			time.Sleep(time.Millisecond * time.Duration(2000+rand.Int63n(1000)))
		} else {
			if s.Option.DataCenter == "" {
				s.Option.DataCenter = result.Allocations[0].Location.DataCenter
			}
			var allocatedMemory int64
			for _, allocation := range result.Allocations {
				s.Market.AddSupply(market.Supply{
					Object: allocation,
				})
				allocatedMemory += allocation.Allocated.MemoryMb
			}
			// log.Printf("%s allocated %d executors with %d MB memory.", s.Master, len(result.Allocations), allocatedMemory)
		}
	}
}