def get_ref_alt_allele(ref, alt, pos):
    """
    Description:
        Helper function to index REF and ALT alleles with genomic positions.

    Arguments:
        ref list: REF alleles.
        alt list: ALT alleles.
        pos list: Genomic positions.

    Returns:
        ref_allele dict: REF alleles.
        alt_allele dict: ALT alleles.
    """
    
    ref_allele = dict()
    alt_allele = dict()

    for i in range(len(pos)):
        r = ref[i]
        a = alt[i]
        p = pos[i]
        ref_allele[p] = r
        alt_allele[p] = a
   
    return ref_allele, alt_allele