code: def createDocument(self, namespaceURI, localName, doctype=None):
          '''If specified must be a SOAP envelope, else may contruct an empty document.
          '''
          prefix = self._soap_env_prefix
  
          if namespaceURI == self.reserved_ns[prefix]:
              qualifiedName = '%s:%s' %(prefix,localName)
          elif namespaceURI is localName is None:
              self.node = self._dom.createDocument(None,None,None)
              return
          else:
              raise KeyError, 'only support creation of document in %s' %self.reserved_ns[prefix]
  
          document = self._dom.createDocument(nsuri=namespaceURI, qname=qualifiedName, doctype=doctype)
          self.node = document.childNodes[0]
  
          #set up reserved namespace attributes
          for prefix,nsuri in self.reserved_ns.items():
              self._setAttributeNS(namespaceURI=self._xmlns_nsuri, 
                  qualifiedName='%s:%s' %(self._xmlns_prefix,prefix), 
                  value=nsurif createDocument(self, namespaceURI, localName, doctype=None):
          '''If specified must be a SOAP envelope, else may contruct an empty document.
          '''
          prefix = self._soap_env_prefix
  
          if namespaceURI == self.reserved_ns[prefix]:
              qualifiedName = '%s:%s' %(prefix,localName)
          elif namespaceURI is localName is None:
              self.node = self._dom.createDocument(None,None,None)
              return
          else:
              raise KeyError, 'only support creation of document in %s' %self.reserved_ns[prefix]
  
          document = self._dom.createDocument(nsuri=namespaceURI, qname=qualifiedName, doctype=doctype)
          self.node = document.childNodes[0]
  
          #set up reserved namespace attributes
          for prefix,nsuri in self.reserved_ns.items():
              self._setAttributeNS(namespaceURI=self._xmlns_nsuri, 
                  qualifiedName='%s:%s' %(self._xmlns_prefix,prefix), 
                  value=nsuri)
docs: If specified must be a SOAP envelope, else may contruct an empty document.