'Set the spacing between grid lines.
Arguments can be x,y,z or spacing=QVector3D().'

def setSpacing(self, x=None, y=None, z=None, spacing=None):

    if (spacing is not None):
        x = spacing.x()
        y = spacing.y()
        z = spacing.z()
    self.__spacing = [x, y, z]
    self.update()
