def opt_password_file(self, filename):
        """
        Specify a file containing username:password login info for
        authenticated connections. (DEPRECATED; see --help-auth instead)
        """
        self['password-file'] = filename
        msg = deprecate.getDeprecationWarningString(
            self.opt_password_file, versions.Version('Twisted', 11, 1, 0))
        warnings.warn(msg, category=DeprecationWarning, stacklevel=2)
        self.addChecker(checkers.FilePasswordDB(filename, cache=True))

        Specify a file containing username:password login info for
        authenticated connections. (DEPRECATED; see --help-auth instead)
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/tap/ftp.py