How do I efficiently find the node *above* a mutation

[hyanwong]

The mutation.node attribute gives the node below a mutation. How do I find the node above a mutation in tskit? E.g. I might want to look up the time of the node immediately above the mutation, without wanting to build the entire tree on which the mutation lies.

[hyanwong]

We now have a mutation.edge attribute, so you can obtain the parent node very simply, without having to build the tree:

mutation = ts.mutation(100)
node_time_below_mutation = ts.nodes_time[mutation.node]
node_time_above_mutation = ts.nodes_time[ts.edges_parent[mutation.edge]]