docs: function WrappedUnionType(attrs, opts) {
    UnionType.call(this, attrs, opts);
  
    this._constructors = this._types.map(function (type) {
      // jshint -W054
      var name = type.getName(true);
      if (name === 'null') {
        return null;
      }
  
      function ConstructorFunction(name) {
        return function Branch$(val) {
          this[`${name}`] = val;
        }
      }
      var constructor = ConstructorFunction(name);
      constructor.getBranchType = function() { return type; };
      return constructor;
    });
  }