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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 edges_unique(self):
 """ The unique edges of the mesh. Returns edges_unique : (n, 2) int Vertex indices for unique edges """

        unique, inverse = grouping.unique_rows(self.edges_sorted)
        edges_unique = self.edges_sorted[unique]
        # edges_unique will be added automatically by the decorator
        # additional terms generated need to be added to the cache manually
        self._cache['edges_unique_idx'] = unique
        self._cache['edges_unique_inverse'] = inverse
        return edges_unique