They are entertaining aren't they, had one about 2.5M long in the horse feed shed, the snake worked really well on rat and mouse control, and after a bit they, well I don't think get friendly is the right term, but perhaps ambivalent about people wandering around.
The cat and the snake however never got on, they would sit and glare at each other for hours, occasionally get into hissing contests. The cat was sudden death for any snakes under about a meter (blacks and browns) but I think they both figured there was a bit too much of the other to try it on.
M