code: static boolean isSubSet(CodeSigner[] subset, CodeSigner[] set)
      {
          // check for the same object
          if (set == subset)
              return true;
  
          boolean match;
          for (int i = 0; i < subset.length; i++) {
              if (!contains(set, subset[i]))
                  return false;
          }
          return true;
      }
docs: returns true if subset is a subset of set