protected @NotNull PsiElement getElementToHighlight(@NotNull YAMLMapping mapping) {
    final PsiElement parent = mapping.getParent();
    if (parent instanceof YAMLDocument) {
      return parent;
    }
    else if (parent instanceof YAMLSequenceItem) {
      final PsiElement key = parent.getFirstChild();
      return key != null ? key : mapping;
    }
    else if (parent instanceof YAMLKeyValue) {
      final PsiElement key = ((YAMLKeyValue)parent).getKey();
      return key != null ? key : mapping;
    }
    else {
      return mapping;
    }
  }
protected @NotNull PsiElement getElementToHighlight(@NotNull YAMLMapping mapping)