def __init__(self, stopwords=None):
    if (stopwords is not None):
        self.stopwords = set(stopwords)
    else:
        self.stopwords = set(nltk.corpus.stopwords.words('english'))
def __init__(self, stopwords=None):
    if (stopwords is not None):
        self.stopwords = set(stopwords)
    else:
        self.stopwords = set(nltk.corpus.stopwords.words('english'))