code: def NextToken(self):
      
      # If we don't have enough data - feed ourselves: We assume
      # that we must have at least one sector in our buffer.
      if len(self.buffer) < 512:
        if self.Feed() == 0 and not self.buffer:
          return None
  
      return Lexer.NextToken(self)
docs: Retrieves the next token.
  
      Returns:
        The next token (instance of Token) or None.