code: function (key, value) {
              var index = this._keys.indexOf(key);
              if (index > -1) {
                  this._keys[index] = key;
                  this._values[index] = value;
              }
              else {
                  this._keys.push(key);
                  this._values.push(value);
              }
              return this;
          }
docs: Sets a key-value pair in this instance.
  @method sjl.stdlib.SjlMap#set
  @param key {*} - Key to set.
  @param value {*} - Value to set.
  @returns {SjlMap}