def _unquotedAttrs(self):
        """
        @return: The I{Content-Type} parameters, unquoted, as a flat list with
            each Nth element giving a parameter name and N+1th element giving
            the corresponding parameter value.
        """
        if self.attrs:
            unquoted = [(k, unquote(v)) for (k, v) in self.attrs.items()]
            return [y for x in sorted(unquoted) for y in x]
        return None

        @return: The I{Content-Type} parameters, unquoted, as a flat list with
            each Nth element giving a parameter name and N+1th element giving
            the corresponding parameter value.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/imap4.py