s anything other than a
        success code an SMTPConnectError is raised.  If specified,
        `local_hostname` is used as the FQDN of the local host in the HELO/EHLO
        command.  Otherwise, the local hostname is found using
        socket.getfqdn(). The `source_address` parameter takes a 2-tuple (host,
        port) for the socket to bind to as its source address before
        connecting. If the host is '' and port is 0, the OS default behavior
        will be used.

        