我想實(shí)現(xiàn)如下所示的接口。我不知道如何開始。有人可以告訴我應(yīng)該如何實(shí)現(xiàn)這些功能嗎？package intervalpackage maintype Interval interface {    contains(r float64) bool // if r is in x, then true    average(Y Intervall) (Intervall, error)    String() string                    //cast interval"[a,b]" to [a,b]    completecontains(Y Intervall) bool //if y is completely in x, give true    New(a, b float64) Intervall    //var a int}type Complex struct {    first int}func (c Complex) contains(r float64) bool {    if a <= r <= b {        return true    } else {        return false    }}func (c Complex) String() string {    return "a"}func (c Complex) length() float64 {    return 2.3}func main() {}