def next(self):
        """
        Return the next token.  Keep track of our current position in the
        config for nice errors.
        """
        if self.current_token == len(self.tokens):
            return None
        token = self.tokens[self.current_token]
        if token["type"] == "newline":
            self.line += 1
            self.line_start = token["start"]
        self.current_token += 1
        if token["type"] == "unknown":
            self.error("Unknown token")
        return token

        Return the next token.  Keep track of our current position in the
        config for nice errors.
        
py3status/parse_config.py