fact: Fixpoint get (C : Type) (x : atom) (E : list (atom*C)) : option C := match E with | nil => None | (y, c) :: F => if eq_atom_dec x y then Some c else get x F end.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.AssocList Metalib.MetatheoryAtom Metalib.LibTactics