code: def extractResponse(cls, request, data):
          
          self = cls()
          self.ns_uri = request.ns_uri
          for field in request.allRequestedFields():
              value = data.get(field)
              if value is not None:
                  self.data[field] = value
          return self
docs: Take a C{L{SRegRequest}} and a dictionary of simple
          registration values and create a C{L{SRegResponse}}
          object containing that data.
  
          @param request: The simple registration request object
          @type request: SRegRequest
  
          @param data: The simple registration data for this
              response, as a dictionary from unqualified simple
              registration field name to string (unicode) value. For
              instance, the nickname should be stored under the key
              'nickname'.
          @type data: {str:str}
  
          @returns: a simple registration response object
          @rtype: SRegResponse