Which goals attention leaves alone — Monty's attention/goal_filter.py.

Attention can propose to look somewhere and a goal filter can refuse it: a goal that lands in a place the attention system has learned to avoid is not worth pursuing this step, however well-specified it is.

Monty declares the filter as a Protocol over __call__(voxel_grid, goals). Here it is a behaviour whose filter/2 is the same call, and the goal it filters is this port's Monty.Cmp.Goal, whose location is nil when the goal does not say where.