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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def add_file(self, path, compress):
 """Add a single file to the MAR file. Args: path (str):
 path to a file to add to this MAR file. compress (str):
 One of 'xz', 'bz2', or None. Defaults to None. """

        if not os.path.isfile(path):
            raise ValueError('{} is not a file'.format(path))
        self.fileobj.seek(self.last_offset)

        with open(path, 'rb') as f:
            flags = os.stat(path).st_mode & 0o777
            self.add_fileobj(f, path, compress, flags)