func Reason(err error) string {
	if err == nil {
		return ""
	}
	if reasoner, ok := err.(Reasoner); ok {
		return reasoner.Reason()
	}
	return ""
}
// Reason returns the error's reason if there is one.
Reason returns the error's reason if there is one.
// Reason returns the error ' s reason if there is one .
func Reason(err error) string {
	if err == nil {
		return ""
	}
	if reasoner, ok := err.(Reasoner); ok {
		return reasoner.Reason()
	}
	return ""
}
func Reason ( err error ) string { if err == nil { return " " } if reasoner , ok := err . ( Reasoner ) ; ok { return reasoner . Reason ( ) } return " " }
Reason returns the error's reason if there is one.
Reason returns the error ' s reason if there is one .