How can the spacing between widgets in a QGridLayout remain fixed on window resize?

I am building an application in

PyQT4

. A principle part of this app will be to maintain a grid of widgets (sub classed from

QLineEdit

widgets). I am organizing the widgets into a

QGridLayout

.

When I run the window, I get a grid organized just how I want, i.e.

However, the

QGridLayout

has the property that it automatically pads the spacing between widgets when the window is resized, i.e.

I would love for the grid to have the same spacing between widgets, no matter how I resize the window. I have looked and cannot seem to find how to accomplish this. I would have imagined something that fixes the spacing, but none of the likely sounding functions have this effect.