(self)
Return the doc_type the datasource.referenced_doc_type
Return the doc_type the datasource.referenced_doc_type
Return the doc_type the datasource . referenced_doc_type
def source_doc_type(self):
        """Return the doc_type the datasource.referenced_doc_type"""
        raise NotImplementedError
def source_doc_type ( self ) : raise NotImplementedError