add_prune_ids: Identify nodes to prune
In dkary/dfgraph: Visualize R Code with Data Flow Graphs

Identify nodes to prune

add_prune_ids(
  flow,
  focus_node = NULL,
  prune_labels = NULL,
  prune_types = "function"
)

`flow`	list of nodes/edges returned by `get_flow`
`focus_node`	numeric: ID of a node to focus upon. Only the dependencies of the specified node will be shown.
`prune_labels`	character: If not NULL, any nodes with labels matching those specified will be pruned (i.e., excluded from the plot) although their dependencies will be cascaded.
`prune_types`	character: Optionally prune nodes based on type (typically "function" and/or "mutate"). Use NULL to override the default of "function".