code: def _literal_exclusions(self, stem: LiteralStemRange,
                              exclusions: List[ShExDocParser.LiteralExclusionContext]) -> None:
          
          for excl in exclusions:
              excl_literal_v = self.context.literal_to_ObjectLiteral(excl.literal()).value
              stem.exclusions.append(LiteralStem(excl_literal_v) if excl.STEM_MARK() else excl_literal_v)
docs: ShExC: literalExclusion = '-' literal STEM_MARK?
              ShExJ: exclusions: [STRING|LiteralStem +]
                     literalStem: {stem:STRING}