def set_edge_label(self, edge, label):
self.set_edge_properties(edge, label=label )<EOL>if not self.DIRECTED:<EOL><INDENT>self.set_edge_properties((edge[<NUM_LIT:1>], edge[<NUM_LIT:0>]) , label=label )<EOL><DEDENT>
Set the label of an edge.

@type  edge: edge
@param edge: One edge.

@type  label: string
@param label: Edge label.