gistfile1.txt

def is_isogram(string):
    string_lower = string.lower()
    for i in string_lower:
        if not i.isalpha():
            continue
        for n in range(string_lower.index(i) - 1, string_lower.index(i) - len(string_lower), -1):
            if string_lower[n] == i:
                print("\"%s\" is not an isogram.") % (string)
                return False
    print("\"%s\" is an isogram!") % (string)
    return True