@Nullable
  private static GrLiteral findLiteral(@NotNull PsiElement psi) {
    PsiElement parent = psi.getParent();
    if (isStringLiteral(parent)) {
      return (GrLiteral)parent;
    }

    if (parent == null) return null;

    PsiElement gParent = parent.getParent();
    if (isStringLiteral(gParent)) {
      return (GrLiteral)gParent;
    }

    if (psi instanceof GrString) {
      return (GrLiteral)psi;
    }

    return null;
  }
@Nullable
  private static GrLiteral findLiteral(@NotNull PsiElement psi)