code: function (key, value, type) {
          var variable = this.values.oneNormalizedVariable(key),
  
              update = { // create an object that will be used as setter
                  key: key,
                  value: value
              };
  
          _.isString(type) && (update.type = type);
  
          // If a variable by the name key exists, update it's value and return.
          // @note adds new variable if existing is disabled. Disabled variables are not updated.
          if (variable && !variable.disabled) {
              variable.update(update);
          }
          else {
              this.values.add(update);
          }
  
          // track the change if mutation tracking is enabled
          this._postman_enableTracking && this.mutations.track(MUTATIONS.SET, key, value);
      }
docs: Creates a new variable, or updates an existing one.
  
  @param {String} key - The name of the variable to set.
  @param {*} value - The value of the variable to be set.
  @param {Variable.types} [type] - Optionally, the value of the variable can be set to a type