code: func otherSource() chan int {
  	c := make(chan int, 0)
  	go func() {
  		defer close(c)
  
  		i := 1
  		for {
  			c <- i
  			i++
  			time.Sleep(time.Second)
  		}
  	}()
  	return c
  }
docs: // otherSource serves as a placeholder from some other source of user input.