will _after you do an EHLO command_, contain the names of the
            SMTP service extensions this server supports, and their
            parameters (if any).

            Note, all extension names are mapped to lower case in the
            dictionary.

    See each method's docstrings for details.  In general, there is a
    method of the same name to perform each SMTP command.  There is also a
    method called 'sendmail' that will do an entire mail transaction.
    r