Imports github.com/AfterShip/email-verifier github.com/deckarep/golang-set/v2 github.com/dimuska139/go-email-normalizer github.com/flosch/pongo2/v6 github.com/vanng822/go-premailer/premailer github.com/xhit/go-simple-mail/v2 Standard library imports fmt net/mail os regexp strings text/template time