code: private int getGroupTypIndicator(PolymerType polymerType) {
  		if(PolymerType.PROTEIN_ONLY.contains(polymerType)){
  			return 1;
  		}
  		if(PolymerType.POLYNUCLEOTIDE_ONLY.contains(polymerType)){
  			return 2;
  		}
  		return 0;
  	}
docs: Get the type of group (0,1 or 2) depending on whether it is an amino aicd (1), nucleic acid (2) or ligand (0)
  @param polymerType
  @return The type of group. (0,1 or 2) depending on whether it is an amino aicd (1), nucleic acid (2) or ligand (0)