code: @Override
      public boolean match(Term term) {
          FunctionEnum fx = term.getFunctionEnum();
          if (fx != PROTEIN_ABUNDANCE) {
              // Protein abundance functions only
              return false;
          }
  
          List<BELObject> args = term.getFunctionArguments();
          if (noItems(args) || args.size() != 2) {
              // Two function arguments only
              return false;
          }
  
          BELObject x = args.get(0);
          if (!(x instanceof Parameter)) {
              // First argument must be a parameter
              return false;
          }
  
          BELObject y = args.get(1);
          if (!(y instanceof Term)) {
              // Second argument must be a term
              return false;
          }
  
          Term ytrm = (Term) y;
          if (!isProteinDecorator(ytrm.getFunctionEnum())) {
              // Protein decorator functions only
              return false;
          }
  
          return true;
      }
docs: {@inheritDoc}