private static PsiType getFunctionalInterfaceTypeByContainingLambda(@NotNull PsiLambdaExpression parentLambda) {
    final PsiType parentInterfaceType = parentLambda.getFunctionalInterfaceType();
    return parentInterfaceType != null ? getFunctionalInterfaceReturnType(parentInterfaceType) : null;
  }
private static PsiType getFunctionalInterfaceTypeByContainingLambda(@NotNull PsiLambdaExpression parentLambda)