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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_edge(self, idx, from_idx, from_lvec, to_idx, to_lvec):
 """ Add information about an edge linking two critical points. This actually describes two edges: from_idx ------ idx ------ to_idx However, in practice, from_idx and to_idx will typically be atom nuclei, with the center node (idx) referring to a bond critical point. Thus, it will be more convenient to model this as a single edge linking nuclei with the properties of the bond critical point stored as an edge attribute. :param idx: index of node :param from_idx: from index of node :param from_lvec: vector of lattice image the from node is in as tuple of ints :param to_idx: to index of node :param to_lvec: vector of lattice image the to node is in as tuple of ints :return: """

        self.edges[idx] = {'from_idx': from_idx, 'from_lvec': from_lvec,
                           'to_idx': to_idx, 'to_lvec': to_lvec}