@Override
    public void println(final String line) {
        if (null == io)
            groovysh.getIo().out.println(line);
        else
            io.out.println(line);
    }
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-console/src/test/java/org/apache/tinkerpop/gremlin/console/jsr223/MockGroovyGremlinShellEnvironment.java