code: def sentence_matches(self, sentence_text):
          
          has_upstream = False
          has_downstream = False
          has_verb = False
  
          # Get the first word of the action type and assume this is the verb
          # (Ex. get depends for depends on)
          actiontype_words = word_tokenize(self.mention.actiontype)
          actiontype_verb_stemmed = stem(actiontype_words[0])
  
          words = word_tokenize(sentence_text)
  
          if self.string_matches_sans_whitespace(sentence_text.lower(),
              self.mention.upstream.lower()):
              has_upstream = True
  
          if self.string_matches_sans_whitespace(sentence_text.lower(),
              self.mention.downstream.lower()):
              has_downstream = True
  
          for word in words:
              if actiontype_verb_stemmed == stem(word):
                  has_verb = True
  
          return has_upstream and has_downstream and has_verb
docs: Returns true iff the sentence contains this mention's upstream
          and downstream participants, and if one of the stemmed verbs in
          the sentence is the same as the stemmed action type.