def create_cds_translation_dict(cdd_genes):
    """Create a dictionary of genes and translations.

    Returns a dictionary, where:
    key = unique translation
    value = set of GeneIDs with that translation."""
    trans_dict = {}
    for cds in cdd_genes:
        trans = cds['Translation']
        gene_id = cds['GeneID']
        if trans in trans_dict.keys():
            trans_dict[trans].add(gene_id)
        else:
            trans_dict[trans] = {gene_id}
    return trans_dict
