errors.go
func ErrInvalidRequestSignature(signature string, err error) error {
	return ErrorResponse{
		Code:    http.StatusForbidden,
		Message: fmt.Sprintf("could not validate request signature: %s", signature),
		Errors:  []Error{Error{Message: err.Error()}},
	}
}
func ErrInvalidRequestSignature(signature string, err error) error {
	return ErrorResponse{
		Code:    http.StatusForbidden,
		Message: fmt.Sprintf("could not validate request signature: %s", signature),
		Errors:  []Error{Error{Message: err.Error()}},
	}
}
// ErrInvalidRequestSignature indicates the payload could not
// be verified with the given signature.