public @Nullable PsiElement getPsiElement(@Nullable T resolvedValue) {
    if (resolvedValue instanceof PsiElement) {
      return (PsiElement)resolvedValue;
    }
    if (resolvedValue instanceof DomElement) {
      return ((DomElement)resolvedValue).getXmlElement();
    }
    return null;
  }
public @Nullable PsiElement getPsiElement(@Nullable T resolvedValue)