private void checkValidityOfIds(Collection<? extends StoreKey> ids) throws StoreException {
      for (StoreKey id : ids) {
        if (!validKeysInStore.contains(id)) {
          throw new StoreException("Not a valid key.", StoreErrorCodes.IDNotFound);
        }
      }
    }
Checks the validity of the {@code ids}
@param ids the {@link StoreKey}s to check
@throws StoreException if the key is not valid
ambry-server/src/test/java/com/github/ambry/server/MockStorageManager.java