@NotNull
  private static Collection<VcsRootError> getInvalidRoots(@NotNull Collection<? extends VcsRootError> errors) {
    return filter(errors, error -> error.getType() == VcsRootError.Type.EXTRA_MAPPING);
  }
@NotNull
  private static Collection<VcsRootError> getInvalidRoots(@NotNull Collection<? extends VcsRootError> errors)