docs: def getSiblings(self, textId, subreference):
          """ Retrieve the siblings of a textual node
  
          :param textId: CtsTextMetadata Identifier
          :param reference: CapitainsCtsPassage Reference
          :return: GetPrevNextUrn request response from the endpoint
          """
          textId = "{}:{}".format(textId, subreference)
          return self.getPrevNextUrn(urn=textId)