@Beta
    public DeleteItemSpec withExpressionSpec(DeleteItemExpressionSpec xspec) {
        return withConditionExpression(xspec.getConditionExpression())
              .withNameMap(xspec.getNameMap())
              .withValueMap(xspec.getValueMap())
              ;
    }
Convenient method to specify expressions (and the associated name map and
value map) via {@link DeleteItemExpressionSpec}.
aws-java-sdk-dynamodb/src/main/java/com/amazonaws/services/dynamodbv2/document/spec/DeleteItemSpec.java