code: function (context) {
          var replacements;
          if (context) {
              replacements = {};
              _gpfObjectForEach(context, function (value, key) {
                  replacements["{" + key + "}"] = value.toString();
              });
              this.message = _gpfStringReplaceEx(this.message, replacements);
          }
      }
docs: Build message by substituting context variables
  
  @param {Object} context Dictionary of named keys
  @since 0.1.5