def id_transcripts_by_gene(self, build='37'):
        """Return a dictionary with hgnc_id as keys and a set of id transcripts as value
        
        Args:
            build(str)
        
        Returns:
            hgnc_id_transcripts(dict)
        """
        hgnc_id_transcripts = {}
        LOG.info("Fetching all id transcripts")
        for gene_obj in self.hgnc_collection.find({'build': build}):
            hgnc_id = gene_obj['hgnc_id']
            id_transcripts = self.get_id_transcripts(hgnc_id=hgnc_id, build=build)
            hgnc_id_transcripts[hgnc_id] = id_transcripts

        return hgnc_id_transcripts
Return a dictionary with hgnc_id as keys and a set of id transcripts as value
        
        Args:
            build(str)
        
        Returns:
            hgnc_id_transcripts(dict)