def show(self,**kwargs):
        timeit = kwargs.get('timeit')
        if timeit:
            start = time.time()
        # todo - we should check for postgis support, and otherwise
        # use the MemoryDatasource
        lyr_adapter = PostgisLayer(self)
        lyr_adapter.show(**kwargs)
        if timeit:
            elapsed = (start - time.time())/60
            print 'render time: %s seconds' % elapsed
dataset/ETHPy150Open springmeyer/djmapnik/djmapnik/managers.py/MapnikQuerySet.show/swapped operands of `-`