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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_label(self, edge):
 """ Get the label of an edge. @type edge: edge @param edge: One edge. @rtype: string @return: Edge label """

        return self.get_edge_properties( edge ).setdefault( self.LABEL_ATTRIBUTE_NAME, self.DEFAULT_LABEL )