code: @Override
      public boolean contains(IElectronContainer electronContainer) {
          if (electronContainer instanceof IBond) return contains((IBond) electronContainer);
          if (electronContainer instanceof ILonePair) return contains((ILonePair) electronContainer);
          if (electronContainer instanceof ISingleElectron) return contains((ISingleElectron) electronContainer);
          return false;
      }
docs: True, if the AtomContainer contains the given ElectronContainer object.
  
  @param  electronContainer ElectronContainer that is searched for
  @return                   true if the AtomContainer contains the given bond object