code: public final static void changeMonomerNotation(int position, PolymerNotation polymer, MonomerNotation not) {
  		polymer.getPolymerElements().getListOfElements().set(position, not);
  	}
docs: method to change the MonomerNotation on the specific position
  
  @param position
  position of the changed MonomerNotation
  @param polymer
  PolymerNotation
  @param not
  changed MonomerNotation