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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 edge_weight(self, edge):
 """ Get the weight of an edge. @type edge: edge @param edge: One edge. @rtype: number @return: Edge weight. """

        return self.get_edge_properties( edge ).setdefault( self.WEIGHT_ATTRIBUTE_NAME, self.DEFAULT_WEIGHT )