def codon_to_int(codon):
    """
    Convert a quaternary codon to an integer, and return the result.
    """
    codon = codon.lower()
    i = 0
    value = 0
    for i in range(3):
        char = codon[-i-1]
        if char == 'a':
            value += 0
        elif char == 'c':
            value += 1 * (4**i)
        elif char == 'g':
            value += 2 * (4**i)
        elif char == 't':
            value += 3 * (4**i)

    return value