code: def check(self, gen):
          
          retval = Counter()
          name, _, block = next(gen, ('', 0, ''))
          if name in self.SAY_THINK:
              if self.is_blank(block.args[0]):
                  retval[self.CORRECT] += 1
              else:
                  name, _, block = next(gen, ('', 0, ''))
                  if name == 'play sound %s until done':
                      # Increment the correct count because we have at least
                      # one successful instance
                      retval[self.CORRECT] += 1
                      # This block represents the beginning of a second
                      retval += self.check(gen)
                  else:
                      retval[self.INCORRECT] += 1
          else:
              retval[self.INCORRECT] += 1
          return retval
docs: Check that the last part of the chain matches.
  
          TODO: Fix to handle the following situation that appears to not work
  
          say 'message 1'
          play sound until done
          say 'message 2'
          say 'message 3'
          play sound until done
          say ''