code: func (conn *Conn) Privmsgf(t, format string, a ...interface{}) {
  	msg := fmt.Sprintf(format, a...)
  	conn.Privmsg(t, msg)
  }
docs: // Privmsgf is the variadic version of Privmsg that formats the message
  // that is sent to the target nick or channel t using the
  // fmt.Sprintf function.