QGIS 2.6 filterByMap

I have this project file:

<!DOCTYPE qgis PUBLIC 'http://ift.tt/1sHLDMf' 'SYSTEM'>
<qgis projectname="" version="2.6.0-Brighton">
    <title>""</title>    
    <properties>        
        <Legend>
            <filterByMap type="bool">true</filterByMap>
        </Legend>
    </properties>
</qgis>

Can i set this property in a python plugin using

QgsProject.instance().writeEntry(""...)

If so, how are the arguments?