pub fn write_graph<N, E, Ix, P>(
graph: &Graph<N, E, Ix>,
path: P,
format: GraphFormat,
weighted: bool,
) -> Result<()>pub fn write_graph<N, E, Ix, P>(
graph: &Graph<N, E, Ix>,
path: P,
format: GraphFormat,
weighted: bool,
) -> Result<()>