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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 terminal_title(self):
 """ Return the current title to be displayed in the terminal. When this in `None`, the terminal title remains the original. """

        result = self.application.get_title()

        # Make sure that this function returns a unicode object,
        # and not a byte string.
        assert result is None or isinstance(result, six.text_type)
        return result