'Return a suitable command for verifying a file.
:param signature_filename: The pathname to the file containing the
signature.
:param data_filename: The pathname to the file containing the
signed data.
:return: The verifying command as a list suitable to be
passed to :class:`subprocess.Popen`.'

def get_verify_command(self, signature_filename, data_filename):

    cmd = [self.gpg, '--status-fd', '2', '--no-tty']
    if self.gpg_home:
        cmd.extend(['--homedir', self.gpg_home])
    cmd.extend(['--verify', signature_filename, data_filename])
    logger.debug('invoking:    %s', '    '.join(cmd))
    return cmd
