python - How to use qgis:selectbylocation in PyQGIS?

I am trying to use the processing toolbox to perform a spatial query (points in polygon). I am not sure how to use the tool and I keep getting Error: Wrong number of parameters.

Here is my script:

polygon_path = r"D:\PythonTesting\SelectByLocation\mitte.shp"
points_path = r"D:\PythonTesting\SelectByLocation\punkte.shp"

polygon = QgsVectorLayer(polygon_path, 'Mitte', 'ogr')
points = QgsVectorLayer(points_path, 'Berlin Punkte', 'ogr')


processing.runalg('qgis:selectbylocation', points, polygon, False, False, False, 0)

I used the documentation, which indicates that I have to use 6 parameters.

However, if I call alghelp the following is returned, indicating 5 parameters:

ALGORITHM: Select by location
    INPUT 
    INTERSECT 
    PREDICATE 

    METHOD 
    OUTPUT 


METHOD(Aktuelle Auswahl ändern mit)
    0 - creating new selection
    1 - adding to current selection
    2 - removing from current selection

Either way I am not getting it to run correctly.

Answer

I used this code:

mapcanvas = iface.mapCanvas()

layers = mapcanvas.layers()

processing.runalg('qgis:selectbylocation', layers[0], layers[1], u'within', 0)

with this situation:

and it worked: