python得到单词模式

def     getWordPattern(word):
        pattern = []
        usedLetter={}
        count=0
        for i in word:
            if i not in usedLetter:
                usedLetter[i]=count
                count+=1
            pattern.append(str(usedLetter[i]))
        return '.'.join(pattern)
def     main():
        print getWordPattern("hello")
if      __name__=="__main__":
        main()