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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(self, error):
 """ Add an error to the tree. :param error: :class:`~cerberus.errors.ValidationError` """

        if not self._path_of_(error):
            self.errors.append(error)
            self.errors.sort()
        else:
            super(ErrorTree, self).add(error)