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: main.go
    path of file: ./repos/learning/golang/source_code/Go语言核心编程代码/chapter11/poly
    
    the code of the file until where you have to start completion: package main
import (
	"fmt"
)

//声明/定义一个接口
type Usb
    
func main() {
	//定义一个Usb接口数组，可以存放Phone和Camera的结构体变量
	//这里就体现出多态数组
	var usbArr [3]Usb
	usbArr[0] = Phone{"vivo"}
	usbArr[1] = Phone{"小米"}
	usbArr[2] = Camera{"尼康"}
	
	fmt.Println(usbArr)

}