Hi,
I'm not sure that's escape proof with just the weights on the corners - I would try and get some binder clips and put at least 4 if not 6 on the top and rim to make sure there are no spots with "give".
These snakes are amazing escape artists and really strong when they get a bit of leveradge. I would be really worried she forced the middle of the lid at one side up and either got out or hurt herself trying.
dr del