code: public static boolean contains(IMolecularFormulaSet formulaSet, IMolecularFormula formula) {
          for (IMolecularFormula fm : formulaSet.molecularFormulas()) {
              if (MolecularFormulaManipulator.compare(fm, formula)) {
                  return true;
              }
          }
          return false;
      }
docs: True, if the IMolecularFormulaSet contains the given IMolecularFormula but not
  as object. It compare according contains the same number and type of Isotopes.
  It is not based on compare objects.
  
  @param formulaSet   The IMolecularFormulaSet
  @param  formula     The IMolecularFormula this IMolecularFormulaSet is searched for
  @return             True, if the IMolecularFormulaSet contains the given formula
  
  @see                IMolecularFormulaSet#contains(IMolecularFormula)