Is there a way to access the GeoProcessing tools in QGIS, in code

[Dil]

Is there a way to access the GeoProcessing tools in QGIS, in code?
I want to find the Difference between two layers and make a new shapefile with the result.It can be manually done by selecting vector->GeoProcessing Tools->Difference. But how to do it in my code? (I use python)
Please help me to find a solution to this problem

[Tim Sutton]

Note this thread has been answered over on inasafe-dev...