package com.google.common.base;
   
   public class SuppliersTestUtils {
       public static void resetMemoizingSupplier(Supplier supplier) {
           if (supplier instanceof Suppliers.MemoizingSupplier) {
               Suppliers.MemoizingSupplier memoizingSupplier = (Suppliers.MemoizingSupplier) supplier;
               memoizingSupplier.initialized = false;
           } else {
               throw new IllegalArgumentException("Passed supplier is not of MemoizingSupplier type");
          }
      }
  }