Robotframework Imported jar library 'SwingLibrary' contains no keywords - jython

Question

I am trying to include SwingLibrary to my robot framework tests. I have downloaded the whole jar with dependencies and added the environment variable JYTHONPATH with the value C:\TMP\JYTHONPATH\SwingLibrary-1.9.6.jar;. I am using :
Robot Framework 3.0.2 (Jython 2.7.0 on java1.7.0_79)
My robot test is pretty simple:
*** Settings ***
Library OperatingSystem
Library SwingLibrary
*** Variables ***
${MESSAGE} Hello, world!
*** Test Cases ***
My Test
[Documentation] Example test
Log ${MESSAGE}
My Keyword /WA
Another Test
Should Be Equal ${MESSAGE} Hello, world!
*** Keywords ***
My Keyword
[Arguments] ${path}
Directory Should Exist ${path}
I run the script using:
jython -vv -m robot -L TRACE -d out tests.robot
It then complains that
Imported library 'SwingLibrary' contains no keywords.
As I ran jython with verbose output I have the following output about SwingLibrary:
import: trying source D:\WA\Z-TMP\test\SwingLibrary
import: trying precompiled with no source D:\WA\Z-TMP\test\SwingLibrary$py.class
import: trying source C:\TMP\JYTHONPATH\SwingLibrary-1.9.6.jar\SwingLibrary
import: trying precompiled with no source C:\TMP\JYTHONPATH\SwingLibrary-1.9.6.jar\SwingLibrary$py.class
import: trying source C:\jython2.7.0\Lib\SwingLibrary
import: trying precompiled with no source C:\jython2.7.0\Lib\SwingLibrary$py.class
import: trying SwingLibrary in packagemanager for path None
import: trying SwingLibrary as java class in SysPathJavaLoader
import: 'SwingLibrary' as java class
import: 'SwingLibrary' as java package
[ WARN ] Imported library 'SwingLibrary' contains no keywords.