bug

def checkio(words_set):
    print words_set        # result  -> set([u'lo', u'hello', u'he'])
    st=list(set(words_set))
    l=len(st)
    x=0
    print st
    for i in range(l-1):
        if st[i].endswith(st[i+1])==1:
            print st[i], st[i+1]
            x+=1
    if x>0:
        return 1
    else:
        return 0
if __name__ == '__main__':
    assert checkio({u"hello", u"lo", u"he"}) == True, "helLO"

My english isn't good, but how i can find suffixes if this [u"hello", u"lo", u"he"] != [u'lo', u'hello', u'he']