def sign_message_file(self, message_file):
        """
        RPC call to format and sign the given message, using the given bip32 path.
        A message file is provided - as produced by eg. Specter wallet.
        Supports RFC6979 only.

        Parameters
        ----------
        message_file : str
            Message file to parse and produce signature for.
            eg:  'signmessage m/84h/0h/0h/0/0 ascii:this is a test message'

        Returns
        -------
        str
            base64-encoded RFC6979 signature
        """
        params = {'message_file': message_file}
        return self._jadeRpc('sign_message', params)

        RPC call to format and sign the given message, using the given bip32 path.
        A message file is provided - as produced by eg. Specter wallet.
        Supports RFC6979 only.

        Parameters
        ----------
        message_file : str
            Message file to parse and produce signature for.
            eg:  'signmessage m/84h/0h/0h/0/0 ascii:this is a test message'

        Returns
        -------
        str
            base64-encoded RFC6979 signature
        
electrum/plugins/jade/jadepy/jade.py