Send mail to one or more recipients. The required arguments are a
        list of RFC 822 to-address strings (a bare string will be treated as a
        list with 1 address), and a message string.

def sendmail(self, to, message):
        """Send mail to one or more recipients. The required arguments are a
        list of RFC 822 to-address strings (a bare string will be treated as a
        list with 1 address), and a message string.

        """

        # If we were passed a bare string as the To: address, convert it to
        # a single element list.
        if isinstance(to, str):
            to = [ to, ]

        # Send one email with the appropriate recipient list.
        server = self._smtp_server()
        server.sendmail(self.get_rfc2822_address(), to, message)
        server.quit()