public static Gas register(Gas gas){
  if (gas == null) {
    return null;
  }
  registeredGasses.add(gas);
  return getGas(gas.getName());
}

public static Gas register ( Gas gas ) { if ( gas == null ) { return null ; } registeredGasses . add ( gas ) ; return getGas ( gas . getName ( ) ) ; }
register a new gas into gasregistry .
