我正在學習 golang 并試圖完成 go 之旅。我被困在切片練習上。在此處復制粘貼問題和我的解決方案。有人可以批評它并告訴我我在這里做錯了什么嗎？問題：Implement Pic. It should return a slice of length dy, each element of which is a slice of dx 8-bit unsigned integers. When you run the program, it will display your picture,interpreting the integers as grayscale (well, bluescale) values.The choice of image is up to you. Interesting functions include (x+y)/2, x*y, and x^y.(You need to use a loop to allocate each []uint8 inside the [][]uint8.)(Use uint8(intValue) to convert between types.)我的解決方案：package mainimport "golang.org/x/tour/pic"func Pic(dx, dy int) [][]uint8 {    ans := make([][]uint8, dy)    for i:=0; i< dy; i++ {        slice := make([]uint8, dx)        for j := 0; j<dx;j++{            slice = append(slice, uint8((i+j)/2))        }        ans = append(ans,slice)    }    return ans}func main() {    pic.Show(Pic)}運行時出現錯誤：恐慌：運行時錯誤：索引超出范圍 [0]，長度為 0我不確定我在這里做錯了什么。另外，為什么在練習中傳遞了一個函數？這是故意的嗎？