code: public static TokenMapper instance(CFMetaData metadata) {
          IPartitioner partitioner = DatabaseDescriptor.getPartitioner();
          if (partitioner instanceof Murmur3Partitioner) {
              return new TokenMapperMurmur(metadata);
          } else {
              return new TokenMapperGeneric(metadata);
          }
      }
docs: Returns a new {@link TokenMapper} instance for the current partitioner using the specified column family
  metadata.
  
  @param metadata The column family metadata.
  @return A new {@link TokenMapper} instance for the current partitioner.