def __init__(
      self,
      ngram_range = (1, 2), min_df=2, max_df=.9):
    """Init parameters for text matcher.

    For details, refer to
    https://scikit-learn.org/stable/modules/generated/sklearn.feature_extraction.text.TfidfVectorizer.html
    since the parameters are used in calling that.

    Args:
      ngram_range: Tuple of n-grams to use (e.g., unigram and bigram)
      min_df: Max allowed term frequency before excluding from vocab
      max_df: Min required term frequency before excluding from vocab
    """
    self._tfidf: Optional[TfidfVectorizer] = None
    self._ngram_range = ngram_range
    self._min_df = min_df
    self._max_df = max_df
Init parameters for text matcher.

    For details, refer to
    https://scikit-learn.org/stable/modules/generated/sklearn.feature_extraction.text.TfidfVectorizer.html
    since the parameters are used in calling that.

    Args:
      ngram_range: Tuple of n-grams to use (e.g., unigram and bigram)
      min_df: Max allowed term frequency before excluding from vocab
      max_df: Min required term frequency before excluding from vocab
    
language/serene/text_matcher.py