code: function(replication_option){
          if( typeof replication_option == 'string'){
              return replication_option;
          }else{
              var properties = [];
              for(var k in replication_option){
                  properties.push(util.format("'%s': '%s'", k, replication_option[k] ));
              }
              return util.format('{%s}', properties.join(','));
          }
      }
docs: Generate replication strategy text for keyspace creation query
  @param  {object|string} replication_option An object or a string representing replication strategy
  @return {string}                    Replication strategy text
  @private