                mail.transport.protocol, mail.host, mail.user, 
                  and mail.from) as the defaults are unlikely to 
                  work in all cases.</dd>
<dd><code>authenticator</code> - Authenticator object.  Used only if a
                        new Session object is created.  Otherwise, 
                        it must match the Authenticator used to create
                        the Session.</dd>
<dt><span class="returnLabel">Returns:</span></dt>
<dd>the default Session object</dd>
<