code: @Override
      public IBond getBond(IAtom atom1, IAtom atom2) {
          for (int i = 0; i < getBondCount(); i++) {
              if (bonds[i].contains(atom1) && bonds[i].getOther(atom1).equals(atom2)) {
                  return bonds[i];
              }
          }
          return null;
      }
docs: {@inheritDoc}