@Test
public void testWithCo() throws ClassNotFoundException, CDKException, Exception {

    IRule rule = new NitrogenRule();
    IMolecularFormula formula = MolecularFormulaManipulator.getMolecularFormula("C43H50CoN4O16", builder);
    formula.setCharge(0);
    Assert.assertEquals(1.0, rule.validate(formula), 0.0001);
}