@Nullable
  public ModifiableWorkspace getModifiableWorkspace() {
    if (myModifiableWorkspace == null && ExternalProjectsWorkspaceImpl.isDependencySubstitutionEnabled()) {
      myModifiableWorkspace = doGetModifiableWorkspace();
    }
    return myModifiableWorkspace;
  }
@Nullable
  public ModifiableWorkspace getModifiableWorkspace()