Ingest a list of DTS Citation object (as parsed JSON-LD) and
        creates the Citation Graph

        :param resource: List of Citation objects from the
            DTS Collection Endpoint (as expanded JSON-LD)
        :type resource: list
        :return: Citation Graph

def ingest(cls, resource):
        """ Ingest a list of DTS Citation object (as parsed JSON-LD) and
        creates the Citation Graph

        :param resource: List of Citation objects from the
            DTS Collection Endpoint (as expanded JSON-LD)
        :type resource: list
        :return: Citation Graph
        """
        _set = cls()
        for data in resource:
            _set.add_child(
                cls.CitationClass.ingest(data, root=_set)
            )
        return _set