docs: private static Map<String, ExpectedAttributeValue> mergeExpectedAttributeValueConditions(
              Map<String, ExpectedAttributeValue> internalAssertions,
              Map<String, ExpectedAttributeValue> userProvidedConditions,
              String userProvidedConditionOperator) {
          // If any of the condition map is null, simply return a copy of the other one.
          if ((internalAssertions == null || internalAssertions.isEmpty())
                  && (userProvidedConditions == null || userProvidedConditions.isEmpty())) {
              return null;
          } else if (internalAssertions == null) {
              return new HashMap<String, ExpectedAttributeValue>(userProvidedConditions);
          } else if (userProvidedConditions == null) {
              return new HashMap<String, ExpectedAttributeValue>(internalAssertions);
          }
  
          // Start from a copy of the internal conditions
          Map<String, ExpectedAttributeValue> mergedExpectedValues =
                  new HashMap<String, ExpectedAttributeValue>(internalAssertions);
  
          // Remove internal conditions that are going to be overlaid by user-provided ones.
          for (String attrName : userProvidedConditions.keySet()) {
              mergedExpectedValues.remove(attrName);
          }
  
          // All the generated internal conditions must be joined by AND.
          // Throw an exception if the user specifies an OR operator, and that the
          // internal conditions are not totally overlaid by the user-provided
          // ones.
          if ( ConditionalOperator.OR.toString().equals(userProvidedConditionOperator)
                  && !mergedExpectedValues.isEmpty() ) {
              throw new IllegalArgumentException("Unable to assert the value of the fields "
                      + mergedExpectedValues.keySet() + ", since the expected value conditions cannot be combined "
                      + "with user-specified conditions joined by \"OR\". You can use SaveBehavior.CLOBBER to "
                      + "skip the assertion on these fields.");
          }
  
          mergedExpectedValues.putAll(userProvidedConditions);
  
          return mergedExpectedValues;
      }