code: def _lemmatize_token(self, token, best_guess=True, return_frequencies=False):
  		
  
  		lemmas = self.lemma_dict.get(token.lower(), None)
  
  		if best_guess == True:
  			if lemmas == None:
  				lemma = token
  			elif len(lemmas) > 1:
  				counts = [self.type_counts[word] for word in lemmas]
  				lemma = lemmas[argmax(counts)]
  			else:
  				lemma = lemmas[0]
  
  			if return_frequencies == True:
  				lemma = (lemma, self._relative_frequency(lemma))
  		else:
  			lemma = [] if lemmas == None else lemmas
  			if return_frequencies == True:
  				lemma = [(word, self._relative_frequency(word)) for word in lemma]
  
  		return(token, lemma)
docs: Lemmatize a single token.  If best_guess is true, then take the most frequent lemma when a form 
  		has multiple possible lemmatizations.  If the form is not found, just return it.
  		If best_guess is false, then always return the full set of possible lemmas, or None if none found.