buildCoder1

def buildCoder(shift):
    """
    Returns a dict that can apply a Caesar cipher to a letter.
    The cipher is defined by the shift value. Ignores non-letter characters
    like punctuation, numbers, and spaces.

    shift: 0 <= int < 26
    returns: dict
    """
    ### TODO
    upperCase = {}
    lowerCase = {}
    upletters = ('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q',
               'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z') 
    lowletters = ('a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q',
               'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z')  
 
    for l in lowletters:
        start = lowletters.index(l)
        stop = lowletters.index(l) + shift
        if stop > 25:
            stop = stop % 26
        lowerCase.update({lowletters[start]:lowletters[stop]}) 
    for l in upletters:
        start = upletters.index(l)
        stop = upletters.index(l) + shift
        if stop > 25:
            stop = stop % 26
        upperCase.update({upletters[start]:upletters[stop]})
    both = dict(upperCase.items() + lowerCase.items())
    return both