import vistrails
import vistrails.core.application
import vistrails.core.api as API

vt_app = vistrails.core.application.init(args=[])

vt_app.new_vistrail()

api = vistrails.core.api.get_api()

api.open_vistrail('examples/gcd.vt')

res = api.execute()

print res[0][0].write_source()