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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 parse_file(self, file_or_fname):
 """ Parse a file or a filename """

        with self._context():
            if hasattr(file_or_fname, 'read'):
                self.filename = getattr(
                    file_or_fname, 'name', file_or_fname.__class__.__name__)
                self.p.ParseFile(file_or_fname)
            else:
                self.filename = file_or_fname
                with open(file_or_fname, 'rb') as f:
                    self.p.ParseFile(f)
        return self._root