Send a message.  If url is None, use the value from the
        constructor (else error). obj is the object (data) to send.
        Data may be described with a requesttypecode keyword, the default 
        is the class's typecode (if there is one), else Any.

        Try to serialize as a Struct, if this is not possible serialize an Array.  If 
        data is a sequence of built-in python data types, it will be serialized as an
        Array, unless requesttypecode is specified.

        arguments:
            url -- 
            opname -- struct wrapper
            obj -- python instance

        key word arguments:
            nsdict -- 
            soapaction --
            wsaction -- WS-Address Action, goes in SOAP Header.
            endPointReference --  set by calling party, must be an 
                EndPointReference type instance.
            soapheaders -- list of pyobj, typically w/typecode attribute.
                serialized in the SOAP:Header.
            requesttypecode --

def Send(self, url, opname, obj, nsdict={}, soapaction=None, wsaction=None, 
             endPointReference=None, soapheaders=(), **kw):
        '''Send a message.  If url is None, use the value from the
        constructor (else error). obj is the object (data) to send.
        Data may be described with a requesttypecode keyword, the default 
        is the class's typecode (if there is one), else Any.

        Try to serialize as a Struct, if this is not possible serialize an Array.  If 
        data is a sequence of built-in python data types, it will be serialized as an
        Array, unless requesttypecode is specified.

        arguments:
            url -- 
            opname -- struct wrapper
            obj -- python instance

        key word arguments:
            nsdict -- 
            soapaction --
            wsaction -- WS-Address Action, goes in SOAP Header.
            endPointReference --  set by calling party, must be an 
                EndPointReference type instance.
            soapheaders -- list of pyobj, typically w/typecode attribute.
                serialized in the SOAP:Header.
            requesttypecode -- 

        '''
        url = url or self.url
        endPointReference = endPointReference or self.endPointReference

        # Serialize the object.
        d = {}
        d.update(self.nsdict)
        d.update(nsdict)

        sw = SoapWriter(nsdict=d, header=True, outputclass=self.writerclass, 
                 encodingStyle=kw.get('encodingStyle'),)
        
        requesttypecode = kw.get('requesttypecode')
        if kw.has_key('_args'): #NamedParamBinding
            tc = requesttypecode or TC.Any(pname=opname, aslist=False)
            sw.serialize(kw['_args'], tc)
        elif not requesttypecode:
            tc = getattr(obj, 'typecode', None) or TC.Any(pname=opname, aslist=False)
            try:
                if type(obj) in _seqtypes:
                    obj = dict(map(lambda i: (i.typecode.pname,i), obj))
            except AttributeError:
                # can't do anything but serialize this in a SOAP:Array
                tc = TC.Any(pname=opname, aslist=True)
            else:
                tc = TC.Any(pname=opname, aslist=False)

            sw.serialize(obj, tc)
        else:
            sw.serialize(obj, requesttypecode)
            
        for i in soapheaders:
           sw.serialize_header(i) 
            
        # 
        # Determine the SOAP auth element.  SOAP:Header element
        if self.auth_style & AUTH.zsibasic:
            sw.serialize_header(_AuthHeader(self.auth_user, self.auth_pass),
                _AuthHeader.typecode)

        # 
        # Serialize WS-Address
        if self.wsAddressURI is not None:
            if self.soapaction and wsaction.strip('\'"') != self.soapaction:
                raise WSActionException, 'soapAction(%s) and WS-Action(%s) must match'\
                    %(self.soapaction,wsaction)

            self.address = Address(url, self.wsAddressURI)
            self.address.setRequest(endPointReference, wsaction)
            self.address.serialize(sw)

        # 
        # WS-Security Signature Handler
        if self.sig_handler is not None:
            self.sig_handler.sign(sw)

        scheme,netloc,path,nil,nil,nil = urlparse.urlparse(url)
        transport = self.transport
        if transport is None and url is not None:
            if scheme == 'https':
                transport = self.defaultHttpsTransport
            elif scheme == 'http':
                transport = self.defaultHttpTransport
            else:
                raise RuntimeError, 'must specify transport or url startswith https/http'

        # Send the request.
        if issubclass(transport, httplib.HTTPConnection) is False:
            raise TypeError, 'transport must be a HTTPConnection'

        soapdata = str(sw)
        self.h = transport(netloc, None, **self.transdict)
        self.h.connect()
        self.SendSOAPData(soapdata, url, soapaction, **kw)