Facter 4 allows blocking of facts at a granular level. You can block any fact from the fact hierarchy, for example, you can block `memory` fact, `memory.swap` or even `memory.swap.available` from the fallowing hierarchy:
memory => { swap => { available => "1.11 GiB", available_bytes => 1196687360, ... }, system => { available => "74.70 MiB", available_bytes => 78327808, ... } }
Blocking works for groups of facts and for individual facts.