duration

var (
	// ErrInvalidFormat indicates the input duration string contains invalid characters
	ErrInvalidFormat = errors.New("invalid duration format")

	// ErrInvalidNumber indicates the numeric part is invalid or not positive
	ErrInvalidNumber = errors.New("invalid duration number")

	// ErrInvalidUnit indicates the unit part is not recognized
	ErrInvalidUnit = errors.New("invalid duration unit")
)