code: function (key) {
                  if (this.has(key)) {
                      var _index = this._keys.indexOf(key);
                      this._values.splice(_index, 1);
                      this._keys.splice(_index, 1);
                  }
                  return this;
              }
docs: Deletes an entry in the `SjlMap`.
  @method sjl.stdlib.SjlMap#delete
  @param key {*} - Key of key-value pair to remove.
  @returns {SjlMap}