def _build_identifier(groupby, name, gene_counter, gene_name):
    return 'rank_genes_{}_{}_{}_{}'.format(groupby, name, gene_counter, gene_name)
def _build_identifier(groupby, name, gene_counter, gene_name):
    return 'rank_genes_{}_{}_{}_{}'.format(groupby, name, gene_counter, gene_name)