def make_new_token(kmer):
    """Write a collapsed k-mer and k-mer reverse complementary as a newtoken
    
    Parameters
    ----------
    kmer: `string`
        String of the alphabet ATCG
        
    Return
    ----------
    newtoken: `string`
        A new token is a new string that combines the input string and its reverser complement "ATnTA"
    """
    kmer = str(kmer).upper()
    newtoken = "n".join(sorted([kmer, kmer.translate(str.maketrans("TAGC", "ATCG"))[::-1]]))
    return newtoken