api

type Calculator interface {
	Add(a ...float64) float64
	Pow(a, b float64) float64
	Divide(a, b float64) (float64, error)
	Avg(a []float64) float64
}

type Utils interface {
	Capitalize(s string) string
	TikTok(ctx context.Context) <-chan time.Time // event
	Panic() int
	Sleep(t time.Duration) error
}