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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 check_token_file(self):
 """ Checks if the token file exists at the given position :return: if file exists or not :rtype: bool """

        # TODO: remove this method in a future release
        warnings.warn('This method will be removed in future versions',
                      DeprecationWarning)
        return self.token_backend.check_token() if hasattr(self.token_backend, 'check_token') else None