func setFrom(mail *sendgrid.SGMail, event *Event) (*sendgrid.SGMail, error) { from, ok := event.Properties["from"] if !ok { from = DefaultFromAddress } if err := mail.SetFrom(from.(string)); err != nil { return nil, err } fromName, ok := event.Properties["fromName"] if !ok { fromName = DefaultFromName } mail.SetFromName(fromName.(string)) return mail, nil }