def __init__(self, context_to_tag, backoff=None):
        SequentialBackoffTagger.__init__(self, backoff)
        self._context_to_tag = (context_to_tag if context_to_tag else {})
:param context_to_tag: A dictionary mapping contexts to tags.
dataset/ETHPy150Open nltk/nltk/nltk/tag/sequential.py/ContextTagger.__init__