def _step1c(self, word):
        if word[-1] == 'y' and len(word) > 2 and self._cons(word, len(word) - 2):
            return word[:-1] + 'i'
        else:
            return word
step1c() turns terminal y to i when there is another vowel in the stem.
dataset/ETHPy150Open nltk/nltk/nltk/stem/porter.py/PorterStemmer._step1c