(self, term)
Returns True if the given term tuple (fieldname, text) is
        in this reader.
Returns True if the given term tuple (fieldname, text) is
        in this reader.
Returns True if the given term tuple ( fieldname text ) is in this reader .
def __contains__(self, term):
        """Returns True if the given term tuple (fieldname, text) is
        in this reader.
        """
        raise NotImplementedError
def __contains__ ( self , term ) : raise NotImplementedError