Make.1-Amodule T : Sidekick_core.TERMmodule Lit : Sidekick_core.LIT with module T = Tmodule P : Sidekick_core.PROOF with type term = T.Term.t and type t = proof and type proof_step = proof_step and type lit = Lit.tval cc_view : T.Term.t -> (T.Fun.t, T.Term.t, T.Term.t Iter.t) Sidekick_core.CC_view.tval is_valid_literal : T.Term.t -> boolIs this a valid boolean literal? (e.g. is it a closed term, not inside a quantifier)