Merging data from multiple channels into a single stream

Given two input channels in1 and in2, and one output channel out. It is required to write a function merge that will listen to both input channels simultaneously and redirect the received values into a single output channel.

package main

import (
 "fmt"
 "math/rand"
 "time"
)

func merge(ch ...<-chan int) <-chan int {
 out := make(chan int)
 // Here you need to implement logic that waits for data from all passed channels
 // and sends it to the out channel
 return out
}

func source(sourceFunc func(int) int) <-chan int {
 ch := make(chan int)
 go func() {
  defer close(ch)
  for i := 0; i < 10; i++ {
   ch <- sourceFunc(i)
   time.Sleep(time.Duration(rand.Intn(3)) * time.Second)
  }
 }()
 return ch
}

func main() {
 rand.Seed(time.Now().UnixMilli())

 in1 := source(func(_ int) int {
  return rand.Intn(7)
 })

 in2 := source(func(i int) int {
  return i
 })

 out := merge(in1, in2)

 for val := range out {
  fmt.Println("Value:", val)
 }
}