docs: function WorkflowVersion(name, version, domain, options) {
    if (!(this instanceof WorkflowVersion)) {
      return new WorkflowVersion(name, version, domain, options);
    }
  
    Fragment.call(this, name);
  
    if (!_.isString(domain)) {
      throw new Error('A `domain` is required');
    }
  
    this.version = version;
    this.domain = domain;
    this.options = options || {};
  }