code: public void putKeyColumnOnlyIfItIsNotYetChangedInTx(final AbstractDynamoDbStore store, final StaticBuffer key, final StaticBuffer column,
          final StaticBuffer expectedValue) {
          expectedValues.computeIfAbsent(store, s -> new HashMap<>());
          expectedValues.get(store).computeIfAbsent(key, k -> new HashMap<>());
          // Ignore any calls to putKeyColumnOnlyIfItIsNotYetChangedInTx if we already have an expected value
          expectedValues.get(store).get(key).putIfAbsent(column, expectedValue);
      }
docs: Puts the expected value for a particular key and column
  @param store the store to put the expected key column value
  @param key the key to put the expected value for
  @param column the column to put the expected value for
  @param expectedValue the expected value to put