## Expand description

Graph utilities.

## Functions§

- Add to
`entered`

that we have entered`node`

and`node`

has`children`

. - Find the next child node, if any, that we have not entered.
- A non-recursive implementation of an infallible depth-first traversal starting from
`root`

. - Same as
`nonrecursive_dft`

, but allows changes to be made to the graph. - A non-recursive implementation of a fallible depth-first traversal starting from
`root`

. - Same as
`try_nonrecursive_dft`

, but allows changes to be made to the graph.