Retrieve the siblings of a textual node

        :param textId: CtsTextMetadata Identifier
        :type textId: str
        :param level: Depth for retrieval
        :type level: int
        :param subreference: CapitainsCtsPassage Reference
        :type subreference: str
        :return: List of references
        :rtype: [str]

def getReffs(self, textId, level=1, subreference=None):
        """ Retrieve the siblings of a textual node

        :param textId: CtsTextMetadata Identifier
        :type textId: str
        :param level: Depth for retrieval
        :type level: int
        :param subreference: CapitainsCtsPassage Reference
        :type subreference: str
        :return: List of references
        :rtype: [str]
        """
        depth = level
        if subreference:
            textId = "{}:{}".format(textId, subreference)
        if subreference:
            if isinstance(subreference, CtsReference):
                depth += subreference.depth
            else:
                depth += (CtsReference(subreference)).depth
        if level:
            level = max(depth, level)
        return self.getValidReff(urn=textId, level=level)