sequenceDiagram
  participant participant_canAcceptChild as canAcceptChild
  participant participant_findNodeById as findNodeById
  participant participant_validateNodePlacement as validateNodePlacement
  participant_validateNodePlacement->>participant_findNodeById: findNodeById()
  participant_findNodeById->>participant_findNodeById: findNodeById()
  participant_findNodeById-->>participant_findNodeById: return
  participant_findNodeById-->>participant_validateNodePlacement: return
  participant_validateNodePlacement->>participant_canAcceptChild: canAcceptChild()
  participant_canAcceptChild-->>participant_validateNodePlacement: return