kubernetes/vendor/github.com/go-errors/errors/error_1_13.go

// find error in any wrapped error
func As(err error, target interface{ … }

// Is detects whether the error is equal to a given error. Errors
// are considered equal by this function if they are matched by errors.Is
// or if their contained errors are matched through errors.Is
func Is(e error, original error) bool { … }