code: def add_capability(self, name, uri):
          
  
          parse_results = urlparse(uri)
          if parse_results.hostname is None:
              # relative URL given, so build this into an absolute URL
              login_url = self.capabilities.get('Login')
              if not login_url:
                  logger.error("There is no login URL stored, so additional capabilities cannot be added.")
                  raise ValueError("Cannot automatically determine absolute path for {0!s} given.".format(uri))
  
              parts = urlparse(login_url)
              port = ':{}'.format(parts.port) if parts.port else ''
              uri = parts.scheme + '://' + parts.hostname + port + '/' + uri.lstrip('/')
  
          self.capabilities[name] = uri
docs: Add a capability of the RETS board
          :param name: The name of the capability
          :param uri: The capability URI given by the RETS board
          :return: None