code: public static BitfinexOrderBookSymbol orderBook(final BitfinexCurrencyPair currencyPair, 
      		final BitfinexOrderBookSymbol.Precision precision,
      		final BitfinexOrderBookSymbol.Frequency frequency, final int pricePoints) {
      	
          if (precision == BitfinexOrderBookSymbol.Precision.R0) {
              throw new IllegalArgumentException("Use BitfinexSymbols#rawOrderBook() factory method instead");
          }
          
          return new BitfinexOrderBookSymbol(currencyPair, precision, frequency, pricePoints);
      }
docs: returns symbol for order book channel
  
  @param currencyPair of order book channel
  @param precision    of order book
  @param frequency    of order book
  @param pricePoints  in initial snapshot
  @return symbol