text: # Natural Language Toolkit: Stemmer Interface
  #
  # Copyright (C) 2001-2008 University of Pennsylvania
  # Author: Trevor Cohn <tacohn@cs.mu.oz.au>
  #         Edward Loper <edloper@gradient.cis.upenn.edu>
  #         Steven Bird <sb@csse.unimelb.edu.au>
  # URL: <http://nltk.sf.net>
  # For license information, see LICENSE.TXT
  
  class StemmerI(object):
      """
      A processing interface for removing morphological affixes from
      words.  This process is known as X{stemming}.
      
      """
      def stem(self, token):
          """
          Strip affixes from the token and return the stem.
  
          @param token: The token that should be stemmed.
          @type token: L{string}
          """
          raise NotImplementedError()
  
  